Answer:
(x + 3)^2 + (y + 2)^2 = 98.
Step-by-step explanation:
(x - h)^2 + (y - k) ^2 = r^2 ( center is (h, k) and r = radius.)
So we have:
(x + 3)^2 + (y + 2)^2 = r^2
When x = 4 y = 5, so
(4 + 3)^2 + (5 + 2)^2 = r^2
r^2 = 7^2 + 7^2 = 98
.
Answer:
Step-by-step explanation:
(x+2)^2+(y+3)^2=100
Suppose a regional computer center wants to evaluate the performance of its disk memory system.One measure of performance is the average time between failures of its disk drive. To estimate this value, the center recorded the time between failures for a random sample of 45 disk-drive failures. The following sample statistics were computed: s . 215 hours # 1,762 hours Estimate the true mean time between failures with a 90% confidence interval. a) ) If the disk memory system is running properly, the true mean time between failures will exceed 1,700 hours. Based on the interval, in part a, what can you infer about the disk memory system?
Answer:
a) solved in attachment
b) If disk is running properly time between failure will exceed then Upper 90 % would be good indicator.
Step-by-step explanation:
A new type of fertilizer is being tested on a plot of land in an orange grove, to see whether it increases the amount of fruit produced. The mean number of pounds of fruit on this plot of land with the old fertilizer was 409 pounds. Agriculture scientists believe that the new fertilizer may decrease the yield. State the appropriate null and alternate hypotheses
a. The null hypothesis is ____________b. The alternate hypothesis is ___________
Answer:
a) Null Hypothesis:[tex]\mu \geq 409[/tex]
b) Alternative hypothesis:[tex]\mu <409[/tex]
Step-by-step explanation:
A hypothesis is defined as "a speculation or theory based on insufficient evidence that lends itself to further testing and experimentation. With further testing, a hypothesis can usually be proven true or false".
The null hypothesis is defined as "a hypothesis that says there is no statistical significance between the two variables in the hypothesis. It is the hypothesis that the researcher is trying to disprove".
The alternative hypothesis is "just the inverse, or opposite, of the null hypothesis. It is the hypothesis that researcher is trying to prove".
On this case we are insterested on the claim that "Agriculture scientists believe that the new fertilizer may decrease the yield". So the system of hypothesis for this case would be:
a) Null Hypothesis:[tex]\mu \geq 409[/tex]
b) Alternative hypothesis:[tex]\mu <409[/tex]
In a population of 1000 subjects, 770 possess a certain characteristic. A sample of 40 subjects selected from this population has 24 subjects who possess the same characteristic. What are the values of the population and sample proportions?
Answer:
0.77,0.60
Step-by-step explanation:
Given that in a population of 1000 subjects, 770 possess a certain characteristic.
A sample of 40 subjects selected from this population has 24 subjects who possess the same characteristic
To find out sample proportion:
Sample size n = 40
Favourable x = 24
Sample proportion p = [tex]\frac{24}{40} =0.60[/tex]
To find out population proportion:
Total population N = 1000
Favourable X = 770
population proportion P = [tex]\frac{770}{1000} =0.77[/tex]
A confidence interval (CI) is desired for the true average stray-load loss u (watts) for a certain type of induction motor when the line current is held at 10 amps for a speed of 1500 rpm. Assume that strayload loss is normally distributed with o = 3.0. (1). Construct a 95% CI for u when n = 25 and x = 58.3. (10 points) (2). Construct a 95% CI for u when n = 100 and 1 = 58.3. (10 points) (3). Construct a 99% CI for u when n = 100 and x = 58.3. (10 points) (4). How large must n be if the half-width of the 99% interval for u is to be 0.5? (10 points)
Creating a 95% confidence interval involves capturing 95% of the probability deviation in a normal distribution. The formula for doing so is (x ± (standard deviation/√n)x critical value). By adjusting the sample size or confidence level accordingly, different intervals can be created.
Explanation:The question inquires about the construction of a
confidence interval
for the true average stray-load loss for a certain type of induction motor. When constructing a 95% confidence interval, we are looking to capture the central 95 percent of the probability on a normal distribution, excluding 2.5 percent on each tail of the distribution.
For point one, with n = 25, x = 58.3, and o = 3.0, use the following formula to construct a 95% Confidence Interval: (x ± (standard deviation/√n)x critical value), resulting in (58.3 ± (3/√25)x 1.96). The same method applies to the rest of the points, only changing the sample size, n, or confidence level.
For the final query, the required sample size, n, can be found by rearranging the formula for confidence intervals and solving for n with the half-width of the interval set at 0.5.
Learn more about Confidence Intervals here:https://brainly.com/question/34700241
#SPJ11
(1). 95% CI (n=25): Standard deviation of 3.0, sample mean of 58.3, yielding a 95% confidence interval of (57.124, 59.476).
(2). 95% CI (n=100): With the same standard deviation and mean, a larger sample size leads to a narrower 95% confidence interval of (57.712, 58.888).
(3). 99% CI (n=100): Expanding the confidence level to 99% increases the margin of error, resulting in a wider interval of (57.5272, 59.0728).
(4). Sample Size (99% CI, ME=0.5): To achieve a half-width of 0.5 for a 99% confidence interval, approximately 956 samples are required.
Given the problem requirements, we will calculate the confidence intervals based on the provided data:
Standard deviation, σ = 3.0Sample mean, x = 58.3Using these values, we’ll calculate the 95% and 99% confidence intervals (CIs) for the population mean, μ:
1. Constructing a 95% CI when n = 25
Calculate the standard error (SE):SE = σ/√n
= 3.0/√25
= 3.0/5
= 0.6
Find the z-value for 95% CI: z = 1.96Margin of error (ME): ME = z * SE= 1.96 * 0.6
= 1.176
Confidence Interval: 58.3 ± 1.176 = (57.124, 59.476)2. Constructing a 95% CI when n = 100
Calculate the standard error (SE):SE = σ/√n
= 3.0/√100
= 3.0/10
= 0.3
Find the z-value for 95% CI: z = 1.96Margin of error (ME): ME = z * SE = 1.96 * 0.3 = 0.588Confidence Interval: 58.3 ± 0.588 = (57.712, 58.888)3. Constructing a 99% CI when n = 100
Calculate the standard error (SE): SE = σ/√n = 3.0/√100 = 3.0/10 = 0.3Find the z-value for 99% CI: z = 2.576Margin of error (ME): ME = z * SE = 2.576 * 0.3 = 0.7728Confidence Interval: 58.3 ± 0.7728 = (57.5272, 59.0728)4. Determining the sample size n for a half-width of 0.5 in the 99% CI
Margin of error (ME): 0.5Find the z-value for 99% CI: z = 2.576Using the formula for margin of error, ME = z * (σ/√n):Solve for n:Therefore, n ≈ 956 to achieve a half-width of 0.5 for a 99% confidence interval.
Given the following null and alternative hypotheses H0: μ1 ≥ μ2 HA: μ1 < μ2 Together with the following sample information (shown below). Assuming that the populations are normally distributed with equal variances, test at the 0.10 level of significance whether you would reject the null hypothesis based on the sample information. Use the test statistic approach. Sample 1 Sample 2 n1 = 14 n2 = 18 x-bar1 = 565 x-bar2 = 578 s1 = 28.9 s2 = 26.3
Answer:
Null hypothesis: [tex]\mu_1 \geq \mu_2[/tex]
Alternative hypothesis: [tex]\mu_1 <\mu_2[/tex]
[tex]t=-1.329[/tex]
[tex]p_v =P(t_{30}<-1.329) =0.0969[/tex]
With the p value obtained and using the significance level given [tex]\alpha=0.1[/tex] we have [tex]p_v<\alpha[/tex] so we can conclude that we have enough evidence to reject the null hypothesis, and we can said that at 10% of significance the mena of the group 1 is significantly lower than the mean for the group 2.
Step-by-step explanation:
When we have two independnet samples from two normal distributions with equal variances we are assuming that
[tex]\sigma^2_1 =\sigma^2_2 =\sigma^2[/tex]
And the statistic is given by this formula:
[tex]t=\frac{(\bar X_1 -\bar X_2)-(\mu_{1}-\mu_2)}{S_p\sqrt{\frac{1}{n_1}}+\frac{1}{n_2}}[/tex]
Where t follows a t distribution with [tex]n_1+n_2 -2[/tex] degrees of freedom and the pooled variance [tex]S^2_p[/tex] is given by this formula:
[tex]\S^2_p =\frac{(n_1-1)S^2_1 +(n_2 -1)S^2_2}{n_1 +n_2 -2}[/tex]
This last one is an unbiased estimator of the common variance [tex]\simga^2[/tex]
The system of hypothesis on this case are:
Null hypothesis: [tex]\mu_1 \geq \mu_2[/tex]
Alternative hypothesis: [tex]\mu_1 <\mu_2[/tex]
Or equivalently:
Null hypothesis: [tex]\mu_1 - \mu_2 \geq 0[/tex]
Alternative hypothesis: [tex]\mu_1 -\mu_2<0[/tex]
Our notation on this case :
[tex]n_1 =14[/tex] represent the sample size for group 1
[tex]n_2 =18[/tex] represent the sample size for group 2
[tex]\bar X_1 =565[/tex] represent the sample mean for the group 1
[tex]\bar X_2 =578[/tex] represent the sample mean for the group 2
[tex]s_1=28.9[/tex] represent the sample standard deviation for group 1
[tex]s_2=26.3[/tex] represent the sample standard deviation for group 2
First we can begin finding the pooled variance:
[tex]\S^2_p =\frac{(14-1)(28.9)^2 +(18 -1)(26.3)^2}{14 +18 -2}=753.882[/tex]
And the deviation would be just the square root of the variance:
[tex]S_p=27.457[/tex]
And now we can calculate the statistic:
[tex]t=\frac{(565 -578)-(0)}{27.457\sqrt{\frac{1}{14}}+\frac{1}{18}}=-1.329[/tex]
Now we can calculate the degrees of freedom given by:
[tex]df=14+18-2=30[/tex]
And now we can calculate the p value using the altenative hypothesis:
[tex]p_v =P(t_{30}<-1.329) =0.0969[/tex]
So with the p value obtained and using the significance level given [tex]\alpha=0.1[/tex] we have [tex]p_v<\alpha[/tex] so we can conclude that we have enough evidence to reject the null hypothesis, and we can said that at 10% of significance the mena of the group 1 is significantly lower than the mean for the group 2.
A statistics instructor believes that fewer than 20% of Evergreen Valley College (EVC) students attended the opening night midnight showing of the latest Harry Potter movie. She surveys 84 of her students and finds that 11 of them attended the midnight showing. At a 1% level of significance, an appropriate conclusion is:
Answer: It is believed that exactly 20% of Evergreen Valley college students attended the opening night midnight showing of the latest harry potter movie.
Step-by-step explanation:
Since we have given that
n = 84
x = 11
So, [tex]\hat{p}=\dfrac{x}{n}=\dfrac{11}{84}=0.13[/tex]
p = 0.20
So, hypothesis:
[tex]H_0:p=\hat{p}\\\\H_a:\hat{p}<p[/tex]
so, test statistic value would be
[tex]z=\dfrac{\hat{p}-p}{\sqrt{\dfrac{p(1-p)}{n}}}\\\\z=\dfrac{0.13-0.20}{\sqrt{\dfrac{0.2\times 0.8}{84}}}\\\\z=-1.604[/tex]
At 1% level of significance, critical value would be
z= 2.58
Since 2.58>-1.604
So, We will accept the null hypothesis.
Hence, It is believed that exactly 20% of Evergreen Valley college students attended the opening night midnight showing of the latest harry potter movie.
20% of Evergreen Valley college students attended the opening night midnight showing of the latest harry potter movie.
The ASQ (American Society for Quality) regularly conducts a salary survey of its membership, primarily quality management professionals. Based on the most recently published mean and standard deviation, a quality control specialist calculated thez-score associated with his own salary and found it was minus2.50. What is his salary?A. 2.5 standard deviations below the average salary.B. 2 and a half times less than the average salary.C. 2.5 standard deviations above the average salary.D. 2 and a half times more than the average salary.
Answer:
A. 2.5 standard deviations below the average salary.
Step-by-step explanation:
Hello!
Usually, when you calculate a probability of an X₀ value from a normally distributed variable you need to standardize it to reach the proper value. In this case, you already have the Z-value and need to reverse the standardization to obtain the X₀ value.
Z= X₀ - μ
δ
δ*Z = X₀ - μ
X₀= (δ*Z) + μ
replace Z= -2.50
X₀= (δ*-2.50) + μ
X₀= μ - (δ*2.50)
You can replace the Z value any time. I've just choose to do it at the end because it's more confortable for me.
I hope it helps!
A cohort study was conducted to study the association of coffee drinking and anxiety in a population-based sample of adults. Among 10,000 coffee drinkers, 500 developed anxiety. Among the 20,000 non-coffee drinkers, 200 cases of anxiety were observed. What is the relative risk of anxiety associated with coffee use?
The relative risk of anxiety associated with coffee use is 5.
Explanation:The relative risk of anxiety associated with coffee use can be calculated by comparing the incidence rates of anxiety among coffee drinkers and non-coffee drinkers. In this study, among 10,000 coffee drinkers, 500 developed anxiety, while among 20,000 non-coffee drinkers, 200 developed anxiety.
To calculate the relative risk, we can use the formula:
Relative Risk = (Incidence Rate of Anxiety among Coffee Drinkers) / (Incidence Rate of Anxiety among Non-Coffee Drinkers)
In this case, the incidence rate of anxiety among coffee drinkers is 500/10,000 = 0.05, and the incidence rate of anxiety among non-coffee drinkers is 200/20,000 = 0.01. Therefore, the relative risk of anxiety associated with coffee use is 0.05/0.01 = 5.
Learn more about relative risk here:https://brainly.com/question/31816694
#SPJ3
Final answer:
To calculate the relative risk of anxiety associated with coffee use, compare the incidence rates of anxiety in coffee drinkers (500/10,000) and non-coffee drinkers (200/20,000) which results in a relative risk of 5.0, indicating that coffee drinkers have a fivefold increased risk of anxiety.
Explanation:
The relative risk of anxiety associated with coffee use can be calculated by comparing the incidence of anxiety among coffee drinkers versus non-coffee drinkers. In the provided scenario, among 10,000 coffee drinkers, 500 developed anxiety, giving us an incidence rate of 500/10,000 or 0.05. Among 20,000 non-coffee drinkers, 200 developed anxiety, with an incidence rate of 200/20,000 or 0.01. Therefore, the relative risk (RR) is calculated as the incidence rate among the exposed (coffee drinkers) divided by the incidence rate among the unexposed (non-coffee drinkers), which is 0.05/0.01 or 5.0. This suggests that the coffee drinkers have a five times higher risk of developing anxiety compared to non-coffee drinkers.
The standard deviation of pulse rates of adult males is less than 12 bpm. For a random sample of 135 adult males, the pulse rates have a standard deviation of 11.5 bpm. Complete parts (a) and (b) below. a. Express the original claim in symbolic form.
Answer:
Step-by-step explanation:
Hello!
The population variance is symbolized σ² and the standard deviation σ (remember that for estimations and statistics test, the parameter of study is always the variance)
The sentence "The standard deviation of pulse rates of adult males is less than 12 bpm." is symbolized σ <12
The sample variance is symbolized S² and the standard deviation is S.
The sample standard deviation is S= 11.5.
I hope it helps!
The symbol σ is used to represent the standard deviation in statistics. So, the standard deviation of pulse rates of adult males being less than 12 bpm in symbolic form is σ < 12. This value tells us that the dispersion of pulse rates among adult males is quite small.
Explanation:The original claim is that the standard deviation of pulse rates of adult males is less than 12 bpm. This can be expressed in symbolic form as follows:
σ < 12
where σ represents the standard deviation.
In the context of this question, the standard deviation is a measure of the dispersion or spread in the pulse rates of adult males. The sample that was taken had a standard deviation of 11.5 bpm, which is less than 12 bpm, thus supporting the original claim.
Learn more about Standard Deviation here:https://brainly.com/question/23907081
#SPJ3
Help with this problem
I got the answer (4,12) (interval notation) 4
Answer:
(4, 12)
Step-by-step explanation:
Simplify (remember to flip the sign when dividing or multiplying by a negative number).
2 − 4 |8 − x| > -14
-4 |8 − x| > -16
|8 − x| < 4
There are two solutions. The first:
8 − x < 4
-x < -4
x > 4
The second solution:
8 − x > -4
-x > -12
x < 12
Therefore, the interval is (4, 12).
The combined math and verbal scores for females taking the SAT-I test are normally distributed with a mean of 998 and a standard deviation of 202 (based on date from the College Board). If a college includes a minimum score of 1025 among its requirements, what percentage of females do not satisfy that requirement?
Approximately 55.39% of females would not meet a college requirement of scoring at least 1025 on the SAT. This is found by calculating the z-score for the minimum required score and looking up the corresponding percentile.
Explanation:To answer this question, we need to calculate the z-score — a statistic that tells us how many standard deviations away a score is from the mean. This formula is Z = (X - μ) / σ, where X is the score, μ is the mean, and σ is the standard deviation.
In this case, X is 1025 (the minimum required score), μ is 998 (the average SAT score), and σ is 202 (the standard deviation). So the z-score is Z = (1025 - 998) / 202 = 0.1336.
This z-score is positive, which means the minimum required score for the college is above the average score. Next, we check a z-score table or use a statistical calculator to find the percentage of scores that fall below this z-score, which gives us the percentage of females not meeting the requirement. For Z = 0.1336, the percentage is approximately 55.39% (using a statistical calculator or z-table). Therefore, roughly 55.39% of females would not meet a college requirement of scoring at least 1025 on the SAT.
Learn more about Statistics here:https://brainly.com/question/31538429
#SPJ12
To find the percentage of females who do not satisfy the minimum score requirement of 1025 on the SAT-I test, we calculate the z-score for the minimum score and find the area under the normal distribution curve. Approximately 55.22% of females do not satisfy the minimum score requirement.
Explanation:To find the percentage of females who do not satisfy the minimum score requirement of 1025 on the SAT-I test, we need to calculate the z-score for the minimum score and then find the area under the normal distribution curve to the left of that z-score. The formula for calculating the z-score is z = (x - μ) / σ, where x is the minimum score, μ is the mean, and σ is the standard deviation. So, z = (1025 - 998) / 202 = 0.1337.
Next, we can use a z-table or a calculator to find the area under the normal distribution curve to the left of a z-score of 0.1337. The area represents the percentage of females who do not satisfy the minimum score requirement. Using a z-table, we can find that the area is approximately 0.5522 or 55.22%.
Therefore, approximately 55.22% of females do not satisfy the minimum score requirement of 1025 on the SAT-I test.
Learn more about the normal distribution curve here:https://brainly.com/question/15276432
#SPJ11
What is the p-value? -- Researcher Jessie is studying how the fear of going to the dentist affects an adult's actual number of visits to the dentist. She asks a random sample of adults whether or not they fear going to the dentist and also how many times they have gone in the past 10 years. She would like to assess if the average number of visits made by adults who fear going to the dentist (Group 1) is higher than the average number of visits for those who don't have that fear (Group 2), that is, test H0: μ1 = μ2 versus Ha: μ1 > μ2, using a 10% significance level. Her random sample of adults resulted in 14 stating they feared going to the dentist and 31 stated they did not fear going to the dentist. The first sample mean was 1.71 pooled standard errors above the second sample mean. Jessie has asked you to provide a complete sketch of the p-value that she can include in her report. You can use the shiny app in R which will give the exact p-value or make a complete sketch by hand and provide the bounds for the p-value using the T table.
2) Jessie also remembers some condition about a normal model required for her two populations of responses. She asks you to check this condition for her. You recall that a QQ plot helps to assess if a population of responses can be considered normally distributed. How many QQ plots do you need to make in this case?
None, since the total sample size of 45 adults is large you can just use the CLT.
One, for the 45 responses (number of visits) reported by the 45 adults that were surveyed.
Two, one for the 14 responses (number of visits) by the adults who fear going to the dentist and one for the 31 responses (number of visits) by the adults who do not fear going to the dentist.
Answer:
Two, one for the 14 responses (number of visits) by the adults who fear going to the dentist and one for the 31 responses (number of visits) by the adults who do not fear going to the dentist.
Step-by-step explanation:
Hello!
1)
You want to test if the average visits to the dentist of people who fear to visit it are greater than the average visits of people that don't fear it.
In this case, the statistic to use is a pooled Student t-test. The reason I've to choose this test is that one of your sample sizes is small (n₁= 14) and the t-test is more accurate for small samples. Even if the second sample is greater than 30, if both variables are normally distributed, the pooled t-test is the one to use.
H₀: μ₁ = μ₂
H₁: μ₁ > μ₂
α: 0.10
t= (X₁[bar]-X₂[bar]) - (μ₁ - μ₂) ~ t[tex]_{n₁+n₂-2}[/tex]
Sₐ√(1/n₁+1/n₂)
Where
X₁[bar] and X₂[bar] are the sample means of both groups
Sₐ is the pooled standard deviation
This is a one-tailed test, you will reject the null hypothesis to big numbers of t. Remember: The p-value is defined as the probability corresponding to the calculated statistic if possible under the null hypothesis (i.e. the probability of obtaining a value as extreme as the value of the statistic under the null hypothesis), and in this case, is also one-tailed.
P(t[tex]_{n₁+n₂-2}[/tex] ≥ t[tex]_{H0}[/tex]) = 1 - P(t[tex]_{n₁+n₂-2}[/tex] < t[tex]_{H0}[/tex])
Where t[tex]_{H0}[/tex] is the value of the calculated statistic.
Since you didn't copy the data of both samples, I cannot calculate it.
2)
Well there was one sample taken and separated in two following the criteria "fears the dentist" and "doesn't fear the dentist" making two different samples, so this is a test for two independent samples. To check if both variables are normally distributed you need to make two QQplots.
I hope it helps!
The p-value represents the probability of the observed data under the null hypothesis. Jessie's study regarding dentist visits requires a p-value sketch based on a test statistic of 1.71 standard errors. Two QQ plots are necessary to check the normality condition of the sample data for both groups.
Explanation:The p-value is a statistical measure that indicates the probability of the observed data or something more extreme occurring under the assumption that the null hypothesis is true. In Researcher Jessie's study, the null hypothesis (H0) is that the mean number of dentist visits for adults who fear going to the dentist (Group 1) is equal to the mean number of visits for those who do not fear going to the dentist (Group 2).
The alternative hypothesis (Ha) is that the mean for Group 1 is greater than the mean for Group 2. Jessie has found that the sample mean for Group 1 is 1.71 pooled standard errors above the mean for Group 2. To sketch the p-value, we need to find the area to the right of the test statistic (1.71 standard errors above the mean) on a normal distribution curve. This area represents the p-value, which we could find using statistical software or by consulting a T table with appropriate degrees of freedom.
Regarding the condition about the normal model, we need to check whether the data is normally distributed to correctly apply the t-test. We would create two QQ plots: one for the 14 responses from adults who fear going to the dentist, and one for the 31 responses from adults who do not.
The QQ plots will help determine if the data for each group deviates from a normal distribution, which is important given the sample sizes are less than 30 and normality cannot be assumed based on the Central Limit Theorem (CLT).
There are four large groups of people, each with 1000 members. Any two of these groups have 100 members in common. Any three of these groups have 10 members in common. And there is 1 person in all four groups. All together, how many people are in these groups?
Answer:
3,359
Step-by-step explanation:
Let A, B, C and D the four groups of people.
Let us denote with |A| the number of elements in a set A.
Then the number of elements of A∪B∪C∪D is the sum of the elements in each group subtracting the elements that have been counted twice.
That is,
|A∪B∪C∪D |=|A|+|B|+|C|+|D| - |A∩B| - |A∩C| - |A∩D| - |B∩C| - |B∩D|- |C∩D| - |A∩B∩C| - |A∩B∩D| - |A∩C∩D| - |B∩C∩ D| - |A∩ B∩C∩ D| =
1000+1000+1000+1000 - 100 - 100 - 100 - 100 - 100 - 100 - 10- 10- 10- 10 - 1 = 3359
Be sure to answer all parts. List the evaluation points corresponding to the midpoint of each subinterval to three decimal places, sketch the function and approximating rectangles and evaluate the Riemann sum to six decimal places if needed. f(x) = x2 + 4,[4, 5], n = 4. Give your answer in an ascending order. Evaluation points: , ,
Answer:
The Riemann Sum for [tex]\int\limits^5_4 {x^2+4} \, dx[/tex] with n = 4 using midpoints is about 24.328125.
Step-by-step explanation:
We want to find the Riemann Sum for [tex]\int\limits^5_4 {x^2+4} \, dx[/tex] with n = 4 using midpoints.
The Midpoint Sum uses the midpoints of a sub-interval:
[tex]\int_{a}^{b}f(x)dx\approx\Delta{x}\left(f\left(\frac{x_0+x_1}{2}\right)+f\left(\frac{x_1+x_2}{2}\right)+f\left(\frac{x_2+x_3}{2}\right)+...+f\left(\frac{x_{n-2}+x_{n-1}}{2}\right)+f\left(\frac{x_{n-1}+x_{n}}{2}\right)\right)[/tex]
where [tex]\Delta{x}=\frac{b-a}{n}[/tex]
We know that a = 4, b = 5, n = 4.
Therefore, [tex]\Delta{x}=\frac{5-4}{4}=\frac{1}{4}[/tex]
Divide the interval [4, 5] into n = 4 sub-intervals of length [tex]\Delta{x}=\frac{1}{4}[/tex]
[tex]\left[4, \frac{17}{4}\right], \left[\frac{17}{4}, \frac{9}{2}\right], \left[\frac{9}{2}, \frac{19}{4}\right], \left[\frac{19}{4}, 5\right][/tex]
Now, we just evaluate the function at the midpoints:
[tex]f\left(\frac{x_{0}+x_{1}}{2}\right)=f\left(\frac{\left(4\right)+\left(\frac{17}{4}\right)}{2}\right)=f\left(\frac{33}{8}\right)=\frac{1345}{64}=21.015625[/tex]
[tex]f\left(\frac{x_{1}+x_{2}}{2}\right)=f\left(\frac{\left(\frac{17}{4}\right)+\left(\frac{9}{2}\right)}{2}\right)=f\left(\frac{35}{8}\right)=\frac{1481}{64}=23.140625[/tex]
[tex]f\left(\frac{x_{2}+x_{3}}{2}\right)=f\left(\frac{\left(\frac{9}{2}\right)+\left(\frac{19}{4}\right)}{2}\right)=f\left(\frac{37}{8}\right)=\frac{1625}{64}=25.390625[/tex]
[tex]f\left(\frac{x_{3}+x_{4}}{2}\right)=f\left(\frac{\left(\frac{19}{4}\right)+\left(5\right)}{2}\right)=f\left(\frac{39}{8}\right)=\frac{1777}{64}=27.765625[/tex]
Finally, use the Midpoint Sum formula
[tex]\frac{1}{4}(21.015625+23.140625+25.390625+27.765625)=24.328125[/tex]
This is the sketch of the function and the approximating rectangles.
A random sample of 85 group leaders, supervisors, and similar personnel at General Motors revealed that, on average, they spent 6.5 years in a particular job before being promoted. The standard deviation of the sample was 1.7 years. Construct a 95% confidence interval.
Final answer:
To construct the 95% confidence interval for the average time spent in a particular job at General Motors, we calculated the margin of error and then added and subtracted it from the sample mean, resulting in a confidence interval of approximately (6.1331, 6.8669).
Explanation:
To construct a 95% confidence interval for the average time spent in a particular job at General Motors, we utilize the sample mean, standard deviation, and the sample size to compute the margin of error and the confidence interval. Given that the sample mean is 6.5 years and the standard deviation is 1.7 years with a sample size of 85, we can calculate the confidence interval as follows:
Firstly, determine the critical value (z*) for a 95% confidence level. Since the population standard deviation is unknown and the sample size is less than 30, we use the t-distribution. For a 95% confidence level and 84 degrees of freedom (n-1), the critical value (using a t-table or software) is approximately 1.989.Compute the standard error of the mean by dividing the standard deviation by the square root of the sample size. Standard error (SE) = 1.7 / sqrt(85) ≈ 0.1845.Calculate the margin of error (MOE) by multiplying the critical value with the standard error. MOE = 1.989 * 0.1845 ≈ 0.3669.Finally, construct the confidence interval by adding and subtracting the margin of error from the sample mean. Lower limit = 6.5 - 0.3669 ≈ 6.1331 and upper limit = 6.5 + 0.3669 ≈ 6.8669. Therefore, the 95% confidence interval is (6.1331, 6.8669).This confidence interval suggests that we are 95% confident that the true average time spent in the job before promotion at General Motors lies between approximately 6.1 and 6.9 years.
Suppose that in your city 39% of the voters are registered as Democrats, 26% as Republicans, and 7% as members of other parties. Voters not aligned with any official party are termed "Independent." You are conducting a poll by calling registered voters at random. In your first three calls, what is the probability that you talk to
a) all Republicans?
b) no Democrats?
c) at least one Independent?
Answer:
a) 0.0176 or 1.76%
b) 0.2270 or 22.70%
c) 0.6268 or 62.68%
Step-by-step explanation:
Democrats: P(D) = 39%
Republicans: P(R) = 26%
Others: P(O) = 7%
Independent: P(I) = 100-39-26-7 =28%
a) Probability of talking to all Republicans in three calls:
[tex]P(N_R=3) =P(R)*P(R)*P(R)\\P(N_R=3) =0.26^3 = 0.0176[/tex]
a) Probability of talking to no democrats in three calls:
[tex]P(N_D=0) =(1-P(D)*(1-P(D)*(1-P(D)\\P(N_D=0) =(1-0.39)^3 = 0.2270[/tex]
c) Probability of talking to at least one independent in three calls:
[tex]P(N_I\geq1)=1-P(N_I=0)\\P(N_I\geq1) = 1-(1-0.28)*(1-0.28)*(1-0.28)\\P(N_I\geq1) = 0.6268[/tex]
a) The probability of talking to all Republicans in the first three calls is 1.7576%. b) The probability of talking to no Democrats in the first three calls is 22.6981%. c) The probability of talking to at least one Independent is 19.5643%.
Explanation:a) To find the probability of talking to all Republicans in the first three calls, we need to multiply the probability of talking to a Republican on each call. The probability of talking to a Republican on the first call is 26%, on the second call is also 26%, and on the third call is still 26%. Therefore, the probability of talking to all Republicans in the first three calls is 0.26 * 0.26 * 0.26 = 0.017576 or 1.7576%.
b) To find the probability of talking to no Democrats in the first three calls, we need to multiply the probability of not talking to a Democrat on each call. The probability of not talking to a Democrat on the first call is 1 - 39% = 61%, on the second call is also 61%, and on the third call is still 61%. Therefore, the probability of talking to no Democrats in the first three calls is 0.61 * 0.61 * 0.61 = 0.226981 or 22.6981%.
c) To find the probability of talking to at least one Independent, we need to subtract the probability of not talking to any Independents from 1. The probability of not talking to an Independent on the first call is 1 - 7% = 93%, on the second call is also 93%, and on the third call is still 93%. Therefore, the probability of not talking to any Independents in the first three calls is 0.93 * 0.93 * 0.93 = 0.804357 or 80.4357%. Since we want the probability of talking to at least one Independent, we subtract this result from 1: 1 - 0.804357 = 0.195643 or 19.5643%.
People are entering a building at a rate modeled by f (t) people per hour and exiting the building at a rate modeled by g (t) people per hour, where t is measured in hours. The functions f and g are nonnegative and differentiable for all times t. Which of the following inequalities indicates that the rate of change of the number of people in the building is increasing at time t? o f (t) > 0 f (t)-9(t) > 0 o f (t)>0 of'(t)-g'(t) > 0
Answer:
The correct option is D) [tex]f'(t)-g'(t) > 0[/tex]
Step-by-step explanation:
Consider the provided information.
People are entering a building at a rate modeled by f (t) people per hour and exiting the building at a rate modeled by g (t) people per hour,
The change of number of people in building is:
[tex]h(x)=f(t)-g(t)[/tex]
Where f(t) is people entering in building and g(t) is exiting from the building.
It is given that "The functions f and g are non negative and differentiable for all times t."
We need to find the the rate of change of the number of people in the building.
Differentiate the above function with respect to time:
[tex]h'(x)=\frac{d}{dt}[f(t)-g(t)][/tex]
[tex]h'(x)=f'(t)-g'(t)[/tex]
It is given that the rate of change of the number of people in the building is increasing at time t.
That means [tex]h'(x)>0[/tex]
Therefore, [tex]f'(t)-g'(t)>0[/tex]
Hence, the correct option is D) [tex]f'(t)-g'(t) > 0[/tex]
The rate of change of the number of people in the building is increasing at time t and with the help of this statement the correct option is D).
Given :
People are entering a building at a rate modeled by f (t) people per hour and exiting the building at a rate modeled by g (t) people per hour, where t is measured in hours. The functions f and g are nonnegative and differentiable for all times t.The change of the number of people in the building is given by:
[tex]h(x) = f(t) - g(t)[/tex]
To determine the inequality, differentiate the above equation with respect to time.
[tex]h'(x)=f'(t)-g'(t)[/tex]
Now, it is given that the rate of change of the number of people in the building is increasing at time t. That means:
[tex]h'(x)>0[/tex]
[tex]f'(t)-g'(t)>0[/tex]
Therefore, the correct option is D).
For more information, refer to the link given below:
https://brainly.com/question/13077606
A sequential circuit has two flip-flops (A and B), one input (X), and one output (Y). When X = 0, the state of the circuit remains the same. When X = 1, the circuit goes through the state transitions from 00 to 10 to 11 to 01, back to 00, and then repeats. Output Y = 1, when AB = 01. Determine the minimized D FF input equations and output equation.
Answer:
The equation for sequential circuit shown in the attachment.
Step-by-step explanation:
USA Today reported that about 47% of the general consumer population in the United States is loyal to the automobile manufacturer of their choice. Suppose Chevrolet did a study of a random sample of 1004 Chevrolet owners and found that 482 said they would buy another Chevrolet. Does this indicate that the population proportion of consumers loyal to Chevrolet is more than 47%? Use α = 0.01.
What is the sample test statistic?
What is the p value of the test statistic?
Answer:
[tex]z=\frac{0.48 -0.47}{\sqrt{\frac{0.47(1-0.47)}{1004}}}=0.635[/tex]
[tex]p_v =P(z>0.635)=1-P(z<0.635)=1-0.737=0.263[/tex]
Step-by-step explanation:
1) Data given and notation n
n=1004 represent the random sample taken
X=482 represent the Chevrolet owners who said they would buy another Chevrolet.
[tex]\hat p=\frac{482}{1004}=0.480[/tex] estimated proportion of Chevrolet owners who said they would buy another Chevrolet.
[tex]p_o=0.47[/tex] is the value that we want to test
[tex]\alpha[/tex] represent the significance level
z would represent the statistic (variable of interest)
[tex]p_v[/tex] represent the p value (variable of interest)
2) Concepts and formulas to use
We need to conduct a hypothesis in order to test the claim that the proportion of Chevrolet owners who said they would buy another Chevrolet is higher than 47%:
Null hypothesis:[tex]p\leq 0.47[/tex]
Alternative hypothesis:[tex]p > 0.47[/tex]
When we conduct a proportion test we need to use the z statisitc, and the is given by:
[tex]z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}[/tex] (1)
The One-Sample Proportion Test is used to assess whether a population proportion [tex]\hat p[/tex] is significantly different from a hypothesized value [tex]p_o[/tex].
3) Calculate the statistic
Since we have all the info requires we can replace in formula (1) like this:
[tex]z=\frac{0.48 -0.47}{\sqrt{\frac{0.47(1-0.47)}{1004}}}=0.635[/tex]
4) Statistical decision
P value method or p value approach . "This method consists on determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.
If we use the significance level provided, [tex]\alpha=0.01[/tex]. The next step would be calculate the p value for this test.
Since is a one side upper test the p value would be:
[tex]p_v =P(z>0.635)=1-P(z<0.635)=1-0.737=0.263[/tex]
So based on the p value obtained and using the significance level assumed [tex]\alpha=0.01[/tex] we have [tex]p_v>\alpha[/tex] so we can conclude that we FAIL to reject the null hypothesis, and we can said that at 1% of significance the proportion of Chevrolet owners who said they would buy another Chevroletis not significantly higher than 0.47 or 47% .
1 point) (Hypothetical.) The average salary of all residents of a city is thought to be about $39,000. A research team surveys a random sample of 200 residents; it happens that the average salary of these 200 is about $40,000 with a SD of $12,000. Make a z-test of the null hypothesis that this difference was just chance (in the sampling).
Answer:
We accept H₀
We don´t have enough evidence to reject H₀
Step-by-step explanation:
Nomal Distribution
population mean μ₀ = 39000
sample size n = 200
sample mean μ = 40000
sample standard deviation s = 12000
Test hypothesis
As we are just interested in look if the difference was just chance, we will do a one tail-test (right)
1.- Hypothesis
H₀ null hypothesis μ₀ = 39000
Hₐ Alternative hypothesis μ₀ > 39000
2.-We considered the confidence interval of 95 % then
α = 0,05 and z(c) = 1.64
3.-Compute z(s)
z(s) = [ ( μ - μ₀ ) ] / 12000/√200 z(s) = [ 40000- 39000)* √200] / 12000
z(s) = 1000*14,14/ 12000 z(s) = 1.1783
4.-Compare
z(s) and z(c)
1.1783 < 1.64
z(s) is inside acceptance region we accep H₀
A trade magazine routinely checks the drive through service times of fast food restaurants. a 90% confidence interval that results from examining 653 customers in one fast food chains drive through has a lower bound of 178.2 secinds and an upper bound of 181.6 seconds.
What does this mean?
a.) one can be 90% confident that the mean deive through serivce time of this fast food chain is 179.9 seconds.
b.) the mean drive through service time of this fast food chain is 179.9 seconds 90% of the time.
c.) there is a 90 % probability that the mean drive through service time of this fast food chain is between 178.2 seconds and 181.6 seconds.
d.) one can be 90% confident that the mean drive through service time of this fast food chain is between 178.2 seconds and 181.6 seconds.
Answer: d) one can be 90% confident that the mean drive through service time of this fast food chain is between 178.2 seconds and 181.6 seconds.
Step-by-step explanation:
The interpretation of 90% confidence interval says that a person can be 90% confident that the true population mean lies in it.
Given : A 90% confidence interval that results from examining 653 customers in one fast food chains drive through has a lower bound of 178.2 seconds and an upper bound of 181.6 seconds.
i.e. 90% confidence interval for population mean drive through service time of fast food restaurants is between 178.2 seconds and 181.6 seconds.
It means a person can be 90% confident that the mean drive through service time of this fast food chain is between 178.2 seconds and 181.6 seconds.
Hence, the correct answer is option d) .one can be 90% confident that the mean drive through service time of this fast food chain is between 178.2 seconds and 181.6 seconds.
Suppose a basketball player has made 217 out of 302 free throws. If the player makes the next 3 free throws, I will pay you $23. Otherwise you pay me $15. Step 1 of 2 : Find the expected value of the proposition. Round your answer to two decimal places. Losses must be expressed as negative values.
Answer:
-$0.90
Step-by-step explanation:
There are only two possible outcomes, winning $23 (W) or losing $15 (L). Therefore:
[tex]P(W) + P(L) = 1[/tex]
The probability of the player making his next 3 free throws (P(W)) is:
[tex]P(W) = \frac{217}{302}*\frac{217}{302}*\frac{217}{302}\\P(W) = 0.37098[/tex]
The probability of the player NOT making his next 3 free throws (P(L)) is:
[tex]P(L) = 1 - P(W) = 1 - 0.37098\\P(L) = 0.62902[/tex]
Expected value (EV) is given by the payoff of each outcome multiplied by its probability:
[tex]EV = (23*0.37098) -(15*0.62902)\\EV = -\$0.90[/tex]
The expected value of the proposition is -$0.90
The quality control manager of a chemical company randomly sampled twenty 100-pound bags of fertilizer to estimate the variance in the pounds of the impurities. The sample variance was found to be 6.62. Find a 95% confidence interval for the population variance in the pounds of impurities. State any assumption you need to make to be able to answer this problem.
Answer:
The 95% confidence interval for the variance in the pounds of impurities would be [tex] 3.829 \leq \sigma^2 \leq 14.121[/tex].
Step-by-step explanation:
1) Data given and notation
[tex]s^2 =6.62[/tex] represent the sample variance
s=2.573 represent the sample standard deviation
[tex]\bar x[/tex] represent the sample mean
n=20 the sample size
Confidence=95% or 0.95
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population mean or variance lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
The Chi square distribution is the distribution of the sum of squared standard normal deviates .
2) Calculating the confidence interval
The confidence interval for the population variance is given by the following formula:
[tex]\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}[/tex]
On this case the sample variance is given and for the sample deviation is just the square root of the sample variance.
The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:
[tex]df=n-1=20-1=19[/tex]
Since the Confidence is 0.95 or 95%, the value of [tex]\alpha=0.05[/tex] and [tex]\alpha/2 =0.025[/tex], and we can use excel, a calculator or a table to find the critical values.
The excel commands would be: "=CHISQ.INV(0.025,19)" "=CHISQ.INV(0.975,19)". so for this case the critical values are:
[tex]\chi^2_{\alpha/2}=32.852[/tex]
[tex]\chi^2_{1- \alpha/2}=8.907[/tex]
And replacing into the formula for the interval we got:
[tex]\frac{(19)(6.62)}{32.852} \leq \sigma^2 \frac{(19)(6.62)}{8.907}[/tex]
[tex] 3.829 \leq \sigma^2 \leq 14.121[/tex]
So the 95% confidence interval for the variance in the pounds of impurities would be [tex] 3.829 \leq \sigma^2 \leq 14.121[/tex].
The confidence interval for the population variance in the pounds of impurities is calculated using the sample variance, the degrees of freedom, and the critical values from a chi-squared distribution. The values are then plugged into the formulas to give the 95% confidence interval for the population variance.
Explanation:The subject of this question is in the field of statistics and it asks about the calculation of the 95% confidence interval for the population variance. In this case, we are trying to estimate the variance in the pounds of impurities in fertilizer bags based on a sample of twenty 100-pound bags with a variance of 6.62.
To solve this, we make the assumption that the population from which the bags are sampled follows a normal distribution. The confidence interval for the variance of a normal distribution can be found using the chi-squared distribution. The formula for this assumes that our samples are independent and identically distributed.
For a 95% confidence interval and d.f. (degrees of freedom) = n - 1 = 20 - 1 = 19, the upper and lower critical values (in this case for a chi-squared distribution, rounded to three decimal places) are 8.231 and 32.852 respectively. We can then use these values in the following formulas:
Lower Limit = sample variance * (d.f. / upper critical value) = 6.62*(19/32.852)
Upper Limit = sample variance * (d.f. / lower critical value) = 6.62*(19/8.231)
Finally, evaluate these to get our confidence interval.
Learn more about Confidence Interval for Variance here:https://brainly.com/question/28155131
#SPJ11
rewrite the statement in conditional form. lines with the same slope are parallel
Answer:
If lines have the same slope, then they are parallel.
Step-by-step explanation:
The first part of the given statement sets up the condition for the second part to be true. A conditional statement makes that explicit.
(lines described by first part) are (lines described by second part) ⇒
if (lines are described by first part), then (lines are described by second part)
Your conditional statement can be written ...
If lines have the same slope, then they are parallel.
Are you smarter than a second grader? A random sample of 60 second graders in a certain school district are given a standardized mathematics skills test. The sample mean score is = 52. Assume the standard deviation of test scores is σ = 15. The nationwide average score on this test is 50. The school superintendent wants to know whether the second graders in her school district have greater math skills than the nationwide average.
This is a one-sample z-test in statistics. You need to set null and alternative hypotheses, calculate the z-score, and compare it to the critical value to test if the mean score of second grade students in the school district significantly exceeds the nationwide average.
Explanation:The subject matter here falls within Statistics, a branch of Mathematics. You want to test whether the mean score of second grade students in the school district is significantly greater than the nationwide average. To solve this, we perform a one-sample z-test, because we know the population standard deviation (σ = 15).
To start, we set the null hypothesis that the mean score for the district is equal to the nationwide average of μ0 = 50. The alternative hypothesis, according to the superintendent's belief, is that the mean score for the district is greater than 50.
You then calculate the z-score, which is the ratio of the difference between the sample mean and the population mean to the standard deviation of the population divided by the square root of the sample size (z = (X-bar - μ0) / (σ / √n). Here, X-bar is 52, n is 60 and σ is 15. After calculating the z-score, you would compare it to the critical z-value for the selected level of significance (typically 0.05 for a two-tailed test). If the calculated z score is larger than the critical z value, you would reject the null hypothesis and accept the alternative hypothesis, thus concluding that the second graders in the district have greater math skills than the nationwide average.
Learn more about One-Sample z-Test here:https://brainly.com/question/31789959
#SPJ6
An airplane with room for 100 passengers has a total baggage limit of 6000 lb. Suppose that the total weight of the baggage checked by an individual passenger is a random variable x with a mean value of 49 lb and a standard deviation of 18 lb. If 100 passengers will board a flight, what is the approximate probability that the total weight of their baggage will exceed the limit? (Hint: With n = 100, the total weight exceeds the limit when the average weight x exceeds 6000/100.) (Round your answer to four decimal places.)
Answer:
[tex]P(\bar x>60)=P(z>6.11)=1-P(z<6.11)=4.98x10^{-10}[/tex]
Is a very improbable event.
Step-by-step explanation:
We want to calculate the probability that the total weight exceeds the limit when the average weight x exceeds 6000/100=60.
If we analyze the situation we this:
If [tex]x_1,x_2,\dots,x_100[/tex] represent the 100 random beggage weights for the n=100 passengers . We assume that for each [tex]i=1,2,3,\dots,100[/tex] for each [tex]x_i[/tex] the distribution assumed is normal with the following parameters [tex]\mu=49, \sigma=18[/tex].
Another important assumption is that the each one of the random variables are independent.
1) First way to solve the problem
The random variable S who represent the sum of the 100 weight is given by:
[tex]S=x_1 +x_2 +\dots +x_100 =\sum_{i=1}^{100} x_i[/tex]
The mean for this random variable is given by:
[tex]E(S)=\sum_{i=1}^{100} E(x_i)=100\mu = 100*49=4900[/tex]
And the variance is given by:
[tex]Var(S)=\sum_{i=1}^{100} Var(x_i)=100(\sigma)^2 = 100*(18)^2[/tex]
And the deviation:
[tex]Sd(S)=\sqrt{100(\sigma)^2} = 10*(18)=180[/tex]
So we have this distribution for S
[tex]S \sim (4900,180)[/tex]
On this case we are working with the total so we can find the probability on this way:
[tex]P(S>6000)=P(z>\frac{6000-4900}{180})=P(z>6.11)=1-P(z<6.11)=4.98x10^{-10}[/tex]
2) Second way to solve the problem
We know that the sample mean have the following distribution:
[tex]\bar X \sim N(\mu,\frac{\sigma}{\sqrt{n}}[/tex]
If we are interested on the probability that the population mean would be higher than 60 we can find this probability like this:
[tex]P(\bar x >60)=P(\frac{\bar x-\mu}{\frac{\sigma}{\sqrt{n}}}>\frac{60-49}{\frac{18}{\sqrt{100}}})[/tex]
[tex]P(z>6.11)=1-P(z<6.11)=4.98x10^{-10}[/tex]
And with both methods we got the same probability. So it's very improbable that the limit would be exceeded for this case.
Find the exact value of csc (–1020)°.
By using reference angle, the exact value of csc (-1020)° is [tex]\frac {-2\sqrt3}{3}[/tex].
How to find the exact value
To find the exact value of csc (-1020)° using the reference angle, first determine the reference angle for -1020°.
To find the reference angle, add or subtract multiples of 360° to bring the angle into the range of 0° to 360°.
-1020° + 360° = -660°
Since -660° is still negative, add another 360°:
-660° + 360° = -300°
Now we have a reference angle of 300°.
The cosecant function (csc) is the reciprocal of the sine function. We know that the sine function is positive in the first and second quadrants, so the cosecant function will be positive in those quadrants.
The exact value of csc(300°) can be found by taking the reciprocal of the sine of 300°:
csc(300°) = 1/sin(300°)
To find the sine of 300°, use the periodicity of the sine function:
sin(300°) = sin(300° - 360°) = sin(-60°)
The sine of -60° is the same as the sine of 60°, but with a negative sign:
sin(-60°) = -sin(60°) = [tex]\frac {-\sqrt3}{2}[/tex]
Now, find the reciprocal:
csc(300°) = 1/(-√3/2) = [tex]\frac {-2}{\sqrt3}[/tex]
To rationalize the denominator, multiply the numerator and denominator by √3:
csc(300°) = [tex]\frac {-2}{\sqrt3}[/tex] * [tex]\frac {\sqrt3}{\sqrt3}[/tex] = [tex]\frac {-2\sqrt3}{3}[/tex]
Therefore, the exact value of csc (-1020)° is [tex]\frac {-2\sqrt3}{3}[/tex].
Complete question
Use reference angle to find the exact value of csc (–1020)°.
A prisoner is trapped in a cell containing 3 doors. The first door leads to a tunnel that returns him to his cell after 2 days’ travel. The second leads to a tunnel that returns him to his cell after 4 days’ travel. The third door leads to freedom after 1 day of travel. If it is assumed that the prisoner will always select doors 1, 2, and 3 with respective probabilities .5, .3, and .2, what is the expected number of days until the prisoner reaches freedom?
1. Repeat problem, assuming the prisoner remembers previously chosen doors, and does not re-choose them. Assume the probabilities for the other doors are proportionally larger.
2. Repeat problem but now suppose there is another cell, and that door 1 takes him to the other cell after 2 days of travel. For the other cell, there are two doors, one of which leads to freedom after 3 days of travel, and the other leads back to the prisoner’s original cell after 3 days of travel; each door is equally likely.
Answer:
dont escape lol
Step-by-step explanation:
the answer is 2
(1 point) The effectiveness of a new bug repellent is tested on 18 subjects for a 10 hour period. Based on the number and location of the bug bites, the percentage of exposed surface area protected from bites was calculated for each of the subjects. Assume the population is normally distributed. The results were as follows: x¯¯¯=92 %, s=8% The new repellent is considered effective if it provides a percent repellency of more than 89%. Using α=0.025, construct a hypothesis test with null hypothesis μ≤0.89 and alternative hypothesis μ>0.89 to determine whether the mean repellency of the new bug repellent is greater than 89% by computing the following: (a)The degree of freedom is df= .
Answer:
z=1.59
If we compare the p value and the significance level given [tex]\alpha=0.025[/tex] we see that [tex]p_v>\alpha[/tex] so we can conclude that we fail to reject the null hypothesis, so we can conclude that the mean repellency of the new bug repellent is greater than 89% at 0.025 of signficance.
Step-by-step explanation:
1) Data given and notation
[tex]\bar X=0.92[/tex] represent the mean effectiveness of a new bug repellent for the sample
[tex]\sigma=0.08[/tex] represent the population standard deviation for the sample
[tex]n=18[/tex] sample size
[tex]\mu_o =0.89[/tex] represent the value that we want to test
[tex]\alpha=0.025[/tex] represent the significance level for the hypothesis test.
t would represent the statistic (variable of interest)
[tex]p_v[/tex] represent the p value for the test (variable of interest)
State the null and alternative hypotheses.
We need to conduct a hypothesis in order to determine if the mean repellency of the new bug repellent is greater than 89% or 0.89, the system of hypothesis would be:
Null hypothesis:[tex]\mu \leq 0.89[/tex]
Alternative hypothesis:[tex]\mu > 0.89[/tex]
We don't know the population deviation, and the sample size <30, so for this case is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:
[tex]t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}[/tex] (1)
t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".
Calculate the statistic
We can replace in formula (1) the info given like this:
[tex]t=\frac{0.92-0.89}{\frac{0.08}{\sqrt{18}}}=1.59[/tex]
Calculate the P-value
First we need to calculate the degrees of freedom given by:
[tex]df=n-1=18-1=17[/tex]
Since is a one-side upper test the p value would be:
[tex]p_v =P(t_{17}>1.59)=0.065[/tex]
In Excel we can use the following formula to find the p value "=1-T.DIST(1.59;17;TRUE)"
Conclusion
If we compare the p value and the significance level given [tex]\alpha=0.025[/tex] we see that [tex]p_v>\alpha[/tex] so we can conclude that we fail to reject the null hypothesis, so we can conclude that the mean repellency of the new bug repellent is greater than 89% at 0.025 of signficance.
6) A cylindrical shaped silo has a diameter of 18 feet and a height of 4 feet. How much water can the silo hold, in terms of π?
The amount of water silo can hold in terms of π is 324π cubic feet
Solution:Given that cylindrical shaped silo has a diameter of 18 feet and a height of 4 feet
To find: Amount of water silo can hold in terms of π
This means we are asked to find the volume of cylindrical shaped silo
The volume of cylinder is given as:
[tex]\text {volume of cylinder }=\pi \mathrm{r}^{2} \mathrm{h}[/tex]
Where "r" is the radius of cylinder
"h" is the height of cylinder
π is the constant has a value 3.14
Given diameter = 18 feet
[tex]radius = \frac{diameter}{2} = \frac{18}{2} = 9[/tex]
Substituting the values in formula, we get
[tex]\text {volume of cylinder }=\pi \times 9^{2} \times 4[/tex]
[tex]\text {volume of cylinder }=\pi \times 81 \times 4=324 \pi[/tex]
Thus amount of water silo can hold in terms of π is 324π cubic feet
Answer:324π
Step-by-step explanation: