Five samples of a ferrous-type substance are to be used to determine if there is a difference between a laboratory chemical analysis and an X-ray fluorescence analysis of the iron content. Each sample was split into two sub-samples and the two types of analysis were applied. Following are the coded data showing the iron content analysis:

Sample
Analysis 1 2 3 4 5
X-rays 2.0 2.0 2.3 2.1 2.4
Chemical 2.2 1.9 2.5 2.3 2.4

Assuming that the populations are normal, test at the 0.05 level of significance whether the two methods of analysis give, on the average, the same result.

Answers

Answer 1

Step-by-step explanation:

Step 1

From the given information,

number of ferrous-type substance, n = 5

Let [tex]\mu_1[/tex] and [tex]\mu_2[/tex] are the true population average for laboratory chemical and X-ray flourescence analysis

Level of significance, [tex]\alpha = 0.05[/tex]

state the null and alternative hypotheses

[tex]H_0 : \mu_1 - \mu_2 = 0\\\\H_1 : \mu_1 - \mu_2 \neq 0[/tex]

Attached are steps 2 to 7 of the remaining solution

Five Samples Of A Ferrous-type Substance Are To Be Used To Determine If There Is A Difference Between
Five Samples Of A Ferrous-type Substance Are To Be Used To Determine If There Is A Difference Between
Five Samples Of A Ferrous-type Substance Are To Be Used To Determine If There Is A Difference Between
Answer 2

Yes, the two methods of analysis give, on average, the same result and this can be determined by using the given data.

Given :

Five samples of a ferrous-type substance are to be used.Each sample was split into two sub-samples and the two types of analysis were applied.0.05 level of significance.

The mean of the first sample is:

[tex]\bar{X_1} = \dfrac{\sum X_1}{n_1}[/tex]

[tex]\bar{X_1} = \dfrac{ 10.8}{5}=2.16[/tex]

Now, the standard deviation of the first sample is:

[tex]S_1 =\sqrt{\dfrac{\sum(X_1-\bar{X_1})^2}{n_1-1}}[/tex]

[tex]S_1 =\sqrt{\dfrac{0.132}{4}}=0.182[/tex]

The mean of the second sample is:

[tex]\bar{X_2} = \dfrac{\sum X_2}{n_2}[/tex]

[tex]\bar{X_2} = \dfrac{ 11.3}{5}=2.26[/tex]

Now, the standard deviation of the second sample is:

[tex]S_2 =\sqrt{\dfrac{\sum(X_2-\bar{X_2})^2}{n_2-1}}[/tex]

[tex]S_2 =\sqrt{\dfrac{0.212}{4}}=0.230[/tex]

Now, the hypothesis test is given below:

Null Hypothesis  --  [tex]H_0:\mu_1=\mu_2[/tex]

Alternative Hypothesis  --  [tex]H_a:\mu_1\neq \mu_2[/tex]

The degree of freedom is calculated as:

[tex]df=n_1+n_2-2\\df=8[/tex]

Now, the formula of the test statistics is given below:

[tex]t = \dfrac{(\bar{X_1}-\bar{X_2})-(\mu_1-\mu_2)}{\sqrt{\dfrac{S^2_1}{n_1}+\dfrac{S^2_2}{n_2}} }[/tex]

[tex]t = \dfrac{2.16-2.26}{\sqrt{\dfrac{(0.182)^2}{5}+\dfrac{(0.230)^2}{5}} }[/tex]

[tex]t = -0.76238688[/tex]

Now, according to the t-value, the p-value is 0.46771. Therefore, the null hypothesis is not rejected.

So, yes the two methods of analysis give, on average, the same result.

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Five Samples Of A Ferrous-type Substance Are To Be Used To Determine If There Is A Difference Between

Related Questions

Jay had $80. He spent 2/5 to buy new running shows. How much did Jay spend?

Answers

Answer:

32$

Step-by-step explanation:

first divide 80 by 5.

(you should get 16)

next multiply by 2

(you should get 32)

this works because out of the 80$ he spent 2/5 of his money. you basically are multiplying the numerators and then dividing by the denominators and because 80 is a whole number it works without having to use the 1.

another way to do it is multiply 80/1 by 2/5

you should get 160/5 and when you simplify you should get 32

Jay spent $32 on new running shoes, which is calculated by taking 2/5 of his original $80.

The solution can be solved as: Jay had $80 and spent 2/5 of his money on new running shoes. To find out how much Jay spent, we need to calculate 2/5 of $80.

First, we divide $80 by 5 to find out how much 1/5 of his money is:

1/5 of $80 = $80 / 5 = $16

Now, we multiply this amount by 2 to get 2/5:

2/5 of $80 = 2 x $16 = $32

So, Jay spent $32 on new running shoes.

There is 60 minutes in a day. How many minutes in 24 hour day

Answers

Answer:

there is 60 minutes in a day or in a hour?

according to 60 min in a hour

Answer: 24*60= 1440 min

Step-by-step explanation:

its impossible to have 60 min in a day.

Final answer:

There are 1440 minutes in a 24 hour day. You can find this by multiplying the number of hours (24) by the number of minutes in an hour (60).

Explanation:

The subject of your question is related to the conversion of units of time. In this case, you want to convert hours into minutes. We know that one hour is equivalent to 60 minutes. Hence, if we want to find out how many minutes are there in a 24 hour day, we will multiply the number of hours (24) by the conversion factor, which is 60 minutes per hour.

So, 24 hours * 60 minutes/hour = 1440 minutes. Therefore, there are 1440 minutes in a 24 hour day. It's straightforward when you use correct conversion factor properly.

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geometry::: please help me ASAP

Answers

Answer:

102

Step-by-step explanation:

ANSWER: 102
hope i helped!

You are at a campus party where there are a total number of n people. The host asked everyone to put their phones in a bowl while walking in. A noise complaint ends the party abruptly, and everyone heads for the door, hastily grabbing their phones from the bowl Assume every guest has one and exactly one phone, and that they pick a phone at random (so that every assignment of a phone to a person is equally likely). What is the probability that: a. Every person gets their phone back? b. The first m persons to pick each get their own phones back? c. The first m persons to pick each get a phone belonging to the last m persons to pick? Hint: Try this thought experiment with a few choices of mand n to get a feel for the numbers that show up.)

Answers

Answer:

1, [tex]\frac{m}{n}[/tex], [tex]\frac{1-m}{n}[/tex].

Step-by-step explanation:

probability = [tex]\frac{Number of Possible Outcomes}{Total Outcomes}[/tex]

Total number of persons in the party = n

a) Pr ( every person gets their phone back) = Pr (each person picks his phone ) multiplied by number of person

   = [tex]\frac{1}{n}[/tex] × n = 1.

     No of first m persons to pick = m

     No of last m persons to pick = 1 - m

b) Pr (first m persons to pick each gets their phones back) = [tex]\frac{m}{n}[/tex]

c) Pr( first m persons get a phone belonging to last m persons) = [tex]\frac{1-m}{n}[/tex]

Hotel cost 60 per night flight cost 150 has a budget of 500 how many nights can she afford

Answers

Answer:

3 nights

Step-by-step explanation:

because 1 flight there and one flight back =300 then add 3 nights =480

Answer:

5 nights or less

Step-by-step explanation:

You can do this by writing an inequality and solving it.

Let n = number of nights.

1 hotel night costs $60. n number of hotel nights cost 60n.

The flight costs $150.

The total cost is the price of the hotel plus the price of the flight.

60n + 150

The total price must be less than or equal to $500.

[tex] 60n + 150 \le 500 [/tex]

Now we solve the inequality.

Subtract 150 from both sides.

[tex] 60n \le 350 [/tex]

Divide both sides by 60.

[tex] n \le \dfrac{350}{60} [/tex]

350 divided by 60 is 5.8333...

[tex] n \le 5.8 [/tex]

The number of night is less than or equal to 5.8, and it must be a whole number, so the most number of nights she can afford is 5.

EXAMPLE 2 Prove that 9ex is equal to the sum of its Maclaurin series. SOLUTION If f(x) = 9ex, then f (n + 1)(x) = for all n. If d is any positive number and |x| ≤ d, then |f (n + 1)(x)| = ≤ 9ed. So Taylor's Inequality, with a = 0 and M = 9ed, says that |Rn(x)| ≤ (n + 1)! |x|n + 1 for |x| ≤ d. Notice that the same constant M = 9ed works for every value of n. But, from this equation, we have lim n → [infinity] 9ed (n + 1)! |x|n + 1 = 9ed lim n → [infinity] |x|n + 1 (n + 1)! = . It follows from the Squeeze Theorem that lim n → [infinity] |Rn(x)| = 0 and therefore lim n → [infinity] Rn(x) = for all values of x. By this theorem, 9ex is equal to the sum of its Maclaurin series, that is, 9ex = [infinity] 9xn n! n = 0 for all x.

Answers

Answer:

To Prove: [tex]9e^x[/tex] is equal to the sum of its Maclaurin series.

Step-by-step explanation:

If [tex]f(x) = 9e^x[/tex], then [tex]f ^{(n + 1)(x)} =9e^x[/tex] for all n. If d is any positive number and   |x| ≤ d, then [tex]|f^{(n + 1)(x)}| = 9e^x\leq 9e^d.[/tex]

So Taylor's Inequality, with a = 0 and M = [tex]9e^d[/tex], says that [tex]|R_n(x)| \leq \dfrac{9e^d}{(n+1)!} |x|^{n + 1} \:for\: |x| \leq d.[/tex]

Notice that the same constant [tex]M = 9e^d[/tex] works for every value of n.

But, since [tex]lim_{n\to\infty}\dfrac{x^n}{n!} =0 $ for every real number x$[/tex],

We have [tex]lim_{n\to\infty} \dfrac{9e^d}{(n+1)!} |x|^{n + 1} =9e^d lim_{n\to\infty} \dfrac{|x|^{n + 1}}{(n+1)!} =0[/tex]

It follows from the Squeeze Theorem that [tex]lim_{n\to\infty} |R_n(x)|=0[/tex] and therefore [tex]lim_{n\to\infty} R_n(x)=0[/tex] for all values of x.

[tex]THEOREM\\If f(x)=T_n(x)+R_n(x), $where $T_n $is the nth degree Taylor Polynomial of f at a and $ lim_{n\to\infty} R_n(x)=0 \: for \: |x-a|<R, $then f is equal to the sum of its Taylor series on $ |x-a|<R[/tex]

By this theorem above, [tex]9e^x[/tex] is equal to the sum of its Maclaurin series, that is,

[tex]9e^x=\sum_{n=0}^{\infty}\frac{9x^n}{n!}[/tex]  for all x.

An industrial company claims that the mean pH level of the water in a nearby river is 6.8. You randomly select 29 water samples and measure the pH of each. The sample mean and standard deviation are 6.7 and 0.35, respectively. Is there enough evidence to reject the company’s claim at the α = 0.05 level of significance?

Answers

Final answer:

The question asks to perform a hypothesis test about the mean pH level in a river. Given a sample size of 29, a sample mean of 6.7, a sample standard deviation of 0.35, and a significance level of α = 0.05, the provided reference suggests that there is insufficient evidence to reject the company's claim of a mean pH of 6.8, due to the calculated p-value being greater than α.

Explanation:

In this problem, we are testing the hypothesis that the mean pH level of water in a nearby river is 6.8. The company claims this as the true population mean. The hypothesis under test is called the Null hypothesis.

Null Hypothesis H0: µ = 6.8Alternative Hypothesis HA: µ ≠ 6.8

The level of significance is given as α = 0.05. We have a sample of size 29 with mean 6.7 and standard deviation 0.35.

In hypothesis testing, we calculate a test statistic and compare it with a critical value corresponding to the level of significance α. Here, we would be calculating a t-score because we have the sample standard deviation, not the population standard deviation and the sample size is less than 30. If the test statistic falls in the critical region, then we reject the null hypothesis.

Without specific calculations, the given reference suggests that the decision is to not reject the null hypothesis, citing p-value > α. In this case, the calculated p-value from testing statistics is higher than 0.05, meaning that the observed test statistic would be quite likely if the null hypothesis is true.

This results in the conclusion that there is insufficient evidence in the sampled data to reject the company's claim of a mean pH of 6.8.

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There is not enough evidence to reject the company's claim at the α=0.05 level of significance.

Given:

Population mean =6.8

Sample mean  =6.7

Sample standard deviation s=0.35

Sample size n=29

Level of significance α=0.05

We'll perform a one-sample t-test since the population standard deviation is unknown and the sample size is less than 30.

The hypotheses are:

Null hypothesis (o):

The mean pH level of the water in the river is 6.8 (μ=6.8).

Alternative hypothesis (H1):

The mean pH level of the water in the river is not equal to 6.8 (≠6.8)

We'll use the formula for the test statistic of a one-sample t-test:

t = (x-  ) / [tex]\frac{s}{\sqrt{n} }[/tex]

t= -0.1/ 0.0651

t≈−1.535

Now, we'll find the critical value for a two-tailed test at α=0.05 significance level with n−1=28 degrees of freedom. Using a t-distribution table or statistical software,

we find the critical values to be approximately ±2.048.

Since −1.535 falls within the range −2.048 to 2.048, we fail to reject the null hypothesis.

So, there is not enough evidence to reject the company's claim at the α=0.05 level of significance.

Find the slope
(-19,-6) (15,16)

Answers

Answer:

11/17

Step-by-step explanation:

slope between two points: slope = (y2 - y1) / (x2 - x1)

(x1, y1) = (-19, -6), (x2, y2) = (15, 16)

m = (16 - ( - 6)) / (15 - ( - 19))

refine

m = 11/17

sorry it is hard to follow... i am on my phone rn :/

Final answer:

The slope between the points (-19, -6) and (15, 16) is 11/17.

Explanation:

To find the slope of the line connecting the points (-19,-6) and (15,16), we will use the slope formula which is the change in y-coordinates divided by the change in x-coordinates. Here is the process:

Identify the coordinates of the two points. Point 1 is (-19, -6), and Point 2 is (15, 16).Apply the slope formula: m = (y2 - y1) / (x2 - x1).Substitute the given values into the formula: m = (16 - (-6)) / (15 - (-19)) = (16 + 6) / (15 + 19).Simplify: m = 22 / 34.Reduce to the simplest form: m = 11 / 17.

Therefore, the slope of the line connecting the two points is 11/17.

Over the past year, the vice president for human resources at a large medical center has run a series of three-month workshops aimed at increasing worker motivation and performance. To check the effectiveness of the workshops, she selected a random sample of 35 employees from the personnel files and recorded their most recent annual performance ratings, along with their ratings prior to attending the workshops. If the vice president for human resources wishes to assess the effectiveness of the workshop in improving performance ratings, what sort of test should she use?

Answers

Answer: She should use THE PAIRED SAMPLE T-TEST.

Step-by-step explanation: The Paired sample t-test, is a method used in statistics to determine whether the mean difference in a statistics is zero. Which shows the accuracy of the two different recorded observation.

The paired sample t-test will help her to evaluate the recorded performance rating of the workers before the workshop, and after attending the workshop.

Example:

Let the mean in the workers performance rating before the workshop be Mb, and after the worship be Ma.

If she wants to find how significant the workshop was.

Ma - Mb = 0 means the workshop did not have any influence in their performance, as their performance remains the same.

Ma - Mb > 0 means that the workshop has improved the performance of the workers. As their mean performance after the workshop is greater than their mean performance before the workshop.

Ma - Mb <0 means that the workshop has reduced the performance of the workers. As their mean performance before the workshop is greater than their mean performance after the workshop.

what is the area of the base.(area=6 square in.x 5 in.

Answers

Answer:

30 square inch

Step-by-step explanation:

[tex]area \: of \: base = 6 \times 5 = 30 \: {inch}^{2} \\ [/tex]

In a random sample of n1 = 156 male Statistics students, there are x1 = 81 underclassmen. In a random sample of n2 = 320 female Statistics students, there are x2 = 221 underclassmen. The researcher would like to test the hypothesis that the percent of males who are underclassmen stats students is less than the percent of females who are underclassmen stats students. What is the p-value for the test of hypothesis? i.e. Find P(Z < test statistic). Enter your answer to 4 decimal places.

Answers

Answer:

The p-value for the test of hypothesis is P(z<-3.617)=0.0002.

Step-by-step explanation:

Hypothesis test on the difference between proportions.

The claim is that the percent of males who are underclassmen stats students (π1) is less than the percent of females who are underclassmen stats students (π2).

Then, the null and alternative hypothesis are:

[tex]H_0: \pi_1-\pi_2=0\\\\H_a:\pi_1-\pi_2<0[/tex]

The male sample has a size n1=156. The sample proportion is p1=81/156=0.52.

The female sample has a size n2=221. The sample proportion in this case is p2=221/320=0.69.

The weigthed average of proportions p, needed to calculate the standard error, is:

[tex]p=\dfrac{n_1p_1+n_2p_2}{n_1+n_2}=\dfrac{81+221}{156+320}=\dfrac{302}{476}= 0.63[/tex]

The standard error for the difference in proportions is:

[tex]\sigma_{p1-p2}=\sqrt{\dfrac{p(1-p)}{n_1}+\dfrac{p(1-p)}{n_2}}=\sqrt{\dfrac{0.63*0.37}{156}+\dfrac{0.63*0.37}{320}}\\\\\\\sigma_{p1-p2}=\sqrt{\dfrac{0.2331}{156}+\dfrac{0.2331}{320}}=\sqrt{0.001503871+0.000728438}=\sqrt{0.002232308}\\\\\\\sigma_{p1-p2}=0.047[/tex]

Then, we can calculate the z-statistic as:

[tex]z=\dfrac{p_1-p_2}{\sigma_{p1-p2}}=\dfrac{0.52-0.69}{0.047}=\dfrac{-0.17}{0.047}=-3.617[/tex]

The P-value for this left tailed test is:

[tex]P-value = P(z<-3.617)=0.00015[/tex]

Answer:

[tex]z=\frac{0.519-0.691}{\sqrt{0.634(1-0.634)(\frac{1}{156}+\frac{1}{320})}}=-3.657[/tex]    

[tex]p_v =P(Z<-3.657)=0.0001[/tex]  

Step-by-step explanation:

Data given and notation  

[tex]X_{1}=81[/tex] represent the number of males underclassmen

[tex]X_{2}=221[/tex] represent the number of females underclassmen

[tex]n_{1}=156[/tex] sample of male

[tex]n_{2}=320[/tex] sample of female

[tex]p_{1}=\frac{81}{156}=0.519[/tex] represent the proportion of males underclassmen

[tex]p_{2}=\frac{221}{320}= 0.691[/tex] represent the proportion of females underclassmen

z would represent the statistic (variable of interest)  

[tex]p_v[/tex] represent the value for the test (variable of interest)  

Concepts and formulas to use  

We need to conduct a hypothesis in order to check if the percent of males who are underclassmen stats students is less than the percent of females who are underclassmen stats students   , the system of hypothesis would be:  

Null hypothesis:[tex]p_{1} \geq p_{2}[/tex]  

Alternative hypothesis:[tex]p_{1} < p_{2}[/tex]  

We need to apply a z test to compare proportions, and the statistic is given by:  

[tex]z=\frac{p_{1}-p_{2}}{\sqrt{\hat p (1-\hat p)(\frac{1}{n_{1}}+\frac{1}{n_{2}})}}[/tex]   (1)  

Where [tex]\hat p=\frac{X_{1}+X_{2}}{n_{1}+n_{2}}=\frac{81+221}{156+320}=0.634[/tex]  

Calculate the statistic  

Replacing in formula (1) the values obtained we got this:  

[tex]z=\frac{0.519-0.691}{\sqrt{0.634(1-0.634)(\frac{1}{156}+\frac{1}{320})}}=-3.657[/tex]    

Statistical decision

For this case we don't have a significance level provided [tex]\alpha[/tex], but we can calculate the p value for this test.    

Since is a one side test the p value would be:  

[tex]p_v =P(Z<-3.657)=0.0001[/tex]  

Harper works as a carpenter for $20.87/h. How much will he earn in a 40-hour workweek? *

Answers

Answer:

$834.8 dollars that week

Step-by-step explanation:

All you have to do is multiply $20.87 by 10 hours to get your answer:)

Final answer:

By multiplying Harper's hourly wage ($20.87) by 40 hours, we determined that Harper will earn $834.80 in a 40-hour workweek.

Explanation:

To calculate how much Harper will earn in a 40-hour work week, you simply need to multiply his hourly wage by the number of hours he works. In this case, that's $20.87 times 40. Using direct multiplication:

$20.87 x 40 = $834.80

So, Harper will earn $834.80 in a 40-hour workweek.

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Taylor and Jesse are buying a magazine for $3.75 and a snack for $2.49 what is s the total cost of the two items?

Answers

Hey There!

The answer you are looking for is; $6.24!

Work:

You simply add $3.75 + $2.49 together.

Since .75 + .29 = 1.24, you carry the one over to the full dollar.

3 + 2 + 1 = 6.

= 6.24

Hope I helped! 5 stars and brainliest are always appreciated.

Answer:

6.24

Step-by-step explanation:

you add the two numbers

Decompose fraction 2 3/4

Answers

Final answer:

To decompose the fraction 2 3/4, convert it to an improper fraction by multiplying the whole number by the denominator of the fraction, add the numerator, and place over original denominator, resulting in 11/4.

Explanation:

The question asks to decompose the fraction 2 3/4 into its components. To decompose this mixed number, we need to convert it to an improper fraction. The process involves multiplying the whole number by the denominator of the fraction part, adding the numerator of the fraction part, and then placing the result over the original denominator.


Multiply the whole number (2) by the denominator of the fraction part (4) which gives us 8.Add the numerator of the fraction part (3) to this result (8 + 3 = 11).Place this total (11) over the original denominator (4) to get the improper fraction 11/4.

Therefore, the mixed number 2 3/4 decomposed into an improper fraction is 11/4.

Suppose a man has ordered twelve 1-gallon paint cans of a particular color (lilac) from the local paint store in order to paint his mother's house. Unknown to the man, three of these cans contains an incorrect mix of paint. For this weekend's big project, the man randomly selects four of these 1-gallon cans to paint his mother's living room. Let x = the number of the paint cans selected that are defective. Unknown to the man, x follows a hypergeometric distribution. Find the probability that none of the four cans selected contains an incorrect mix of paint.

Answers

Answer:

The probability that none of the four cans selected contains an incorrect mix of paint is P=0.2545.

Step-by-step explanation:

We have 12 cans, out of which 3 are defective (incorrect mix of paint).

The man will choose 4 cans to paint his mother's house living room.

Let x = the number of the paint cans selected that are defective.

The variable x is known to follow a hypergeometric distribution.

The probability of getting k=0 defectives in a selected sample of K=4 cans, where there are n=3 defectives in the population of N=12 cans is:

[tex]P(X=k)=\dfrac{\binom{K}{k}\binom{N-K}{n-k}}{\binom{N}{n}}\\\\\\\\ P(X=0)=\dfrac{\binom{4}{0}\binom{12-4}{3-0}}{\binom{12}{3}}=\dfrac{\binom{4}{0}\binom{8}{3}}{\binom{12}{3}}=\dfrfac{1*56}{220}=\dfrac{56}{220}=0.2545[/tex]

The probability that none of the four cans selected contains an incorrect mix of paint is P=0.2545.

Final answer:

The probability that none of the four randomly selected cans are defective is approximately 0.2545, or 25.45%, which is determined using the hypergeometric distribution.

Explanation:

The student is faced with a scenario where a man has twelve 1-gallon paint cans, out of which three contain an incorrect mix of paint. The man randomly selects four of these cans to paint with, and the question is to find the probability that none of the four selected cans are defective, which follows the hypergeometric distribution.

The relevant parameters for the hypergeometric distribution in this scenario are: the total number of cans (N=12), the number of defective cans (K=3), the number of cans selected (n=4), and the number of defective cans selected that we are interested in (x=0). To compute the probability, we use the hypergeometric probability formula:

P(X = x) = [(C(K, x) * C(N-K, n-x)) / C(N, n)]

Substituting the given values, we have:

P(X = 0) = [(C(3, 0) * C(12-3, 4-0)) / C(12, 4)]
= [(1 * C(9, 4)) / C(12, 4)]
= (1 * 126) / 495
≈ 0.2545

This means the probability that none of the four randomly selected cans are defective is approximately 0.2545, or 25.45%.

A professor at a local university noted that the grades of her students were normally distributed with a mean of 78 and a standard deviation of 10. The professor has informed us that 16.6 percent of her students received grades of A. What is the minimum score needed to receive a grade of A?

Answers

Final answer:

To find the minimum score needed to receive a grade of A, we need to determine the cutoff point for the top 16.6% of students. We can use the Z-score formula to convert a raw score into a standardized score and then find the corresponding raw score. The minimum score needed to receive a grade of A is approximately 88.

Explanation:

To find the minimum score needed to receive a grade of A, we need to determine the cutoff point for the top 16.6% of students. In a normal distribution, we can use the Z-score formula to convert a raw score into a standardized score. We need to find the Z-score that corresponds to the 83.4th percentile, as 16.6 percent is the area to the left of this score. We can then use the Z-score formula to find the corresponding raw score.

Z = (X - μ) / σ

Where: Z is the Z-score, X is the raw score, μ is the mean, and σ is the standard deviation. Rearranging the formula, we have:

X = (Z * σ) + μ

Since the mean is 78 and the standard deviation is 10, we substitute the values into the formula:

X = (Z * 10) + 78

Next, we need to find the Z-score that corresponds to the 83.4th percentile using a Z-score table or a calculator. From the table, we find that the Z-score is approximately 0.9998. Substituting this value into the formula, we can solve for X:

X = (0.9998 * 10) + 78

X = 9.998 + 78

X ≈ 87.998

Therefore, the minimum score needed to receive a grade of A is approximately 88.

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A survey of data base administrators is conducted. In a random sample of equation, n=150, x=63 of them were found to have over 10 years of experience. Construct 1-a=0.90 confidence interval for the population proportion p of data base administrators with over 10 years of experience.____________________________________________________________1) The sample proportion of data base administrators having over 10 years of experiences is closest toa.63 b.1.645 c.4.2 d.42 e.none of the above2) The half width of this confidence interval is closest to a.0.0033 b.0.0403 c.0.0663 d.0.0790 e.none of the above3) The left limit of this confidence interval L is closest to a.0.4990 b.0.4863 c.0.3537 d.0.3140 e.none of the above4) The right limit of this confidence interval R is closest to a.0.4990 b.0.4863 c.0.3537 d.0.3410 e.none of the above5) The conclusion is a.With 90% confidence, 0.3410 < p < 0.4863 b.With 90% confidence, 0.3537 < p < 0.4990 c.With 90% confidence, 0.3410 < p < 0.4990 d.With 90% confidence, 0.3537 < p < 0.4863 e.none of the above

Answers

Answer:

Step-by-step explanation:

Sample proportion is x/n

Where

p = probability of success

n = number of samples

p = x/n = 63/150 = 0.42

q = 1 - p = 1 - 0.42 = 0.58

To determine the z score, we subtract the confidence level from 100% to get α

Since 1 - α = 0.9

α = 1 - 0.9 = 0.1

α/2 = 0.1/2 = 0.05

This is the area in each tail. Since we want the area in the middle, it becomes

1 - 0.05 = 0.95

The z score corresponding to the area on the z table is 1.645. Thus, confidence level of 90% is 1.645

Confidence interval is written as

(Sample proportion ± margin of error)

Margin of error = z × √pq/n

= 1.645 × √(0.42 × 0.58)/150

= 0.066

The lower end of the confidence interval is

0.42 - 0.066 = 0.354

The upper end of the confidence interval is

0.42 + 0.066 = 0.486

Therefore, the answers to the given questions are

1) d. 0.42

2) the quantity after the ± is the half width. It is also the margin of error. Thus

The half width of this confidence interval is closest to

d. 0.0663

3) c.0.3537

4) b.0.4863

5) d.With 90% confidence, 0.3537 < p < 0.4863

Consider the relationship between the number of bids an item on eBay received and the item's selling price. The following is a sample of 5 items sold through an auction. Price in Dollars 26 29 32 38 47 Number of Bids 12 13 15 16 18 Step 3 of 3 : Calculate the correlation coefficient, r. Round your answer to three decimal places.\

Answers

Answer:

Let's assume the following data:

Price in Dollars (X) 26 29 32 38 47

Number of Bids (Y) 12 13 15 16 18

For our case we have this:

n=10 [tex] \sum x = 172, \sum y = 74, \sum xy = 2623, \sum x^2 =6194, \sum y^2 =1118[/tex]  

[tex]r=\frac{5(2623)-(172)(74)}{\sqrt{[5(6194) -(172)^2][5(1118) -(74)^2]}}=0.974[/tex]  

So then the correlation coefficient would be r =0.974

Step-by-step explanation:

Previous concepts

The correlation coefficient is a "statistical measure that calculates the strength of the relationship between the relative movements of two variables". It's denoted by r and its always between -1 and 1.

Solution to the problem

And in order to calculate the correlation coefficient we can use this formula:  

[tex]r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{[n\sum x^2 -(\sum x)^2][n\sum y^2 -(\sum y)^2]}}[/tex]  

Let's assume the following data

Price in Dollars (X) 26 29 32 38 47

Number of Bids (Y) 12 13 15 16 18

For our case we have this:

n=10 [tex] \sum x = 172, \sum y = 74, \sum xy = 2623, \sum x^2 =6194, \sum y^2 =1118[/tex]  

[tex]r=\frac{5(2623)-(172)(74)}{\sqrt{[5(6194) -(172)^2][5(1118) -(74)^2]}}=0.974[/tex]  

So then the correlation coefficient would be r =0.974

An ant moves along the x-axis from left to right at 5 inches per second. A spider moves along the y-axis from up to down at 3 inches per second. At a certain instant, the ant is 4 inches to the right of the origin and the spider is 8 inches above the origin. At this instant, what is the rate of change of the distance between the spider and the ant

Answers

Answer: The rate of change of the distance between the spider and the ant is 4.92 inches/sec

Step-by-step explanation: Please see the attachments below

The mayor of a town has proposed a plan for the annexation of an adjoining community. A political study took a sample of 1000 voters in the town and found that 54% of the residents favored annexation. Using the data, a political strategist wants to test the claim that the percentage of residents who favor annexation is more than 50%. Determine the P-value of the test statistic. Round your answer to four decimal places.

Answers

Answer:

[tex]z=\frac{0.54 -0.5}{\sqrt{\frac{0.5(1-0.5)}{1000}}}=2.530[/tex]  

[tex]p_v =P(z>2.530)=0.0057[/tex]  

Step-by-step explanation:

Data given and notation

n=1000 represent the random sample taken

[tex]\hat p=0.54[/tex] estimated proportion of residents that favored the annexation

[tex]p_o=0.5[/tex] is the value that we want to test

z would represent the statistic (variable of interest)

[tex]p_v[/tex] represent the p value (variable of interest)  

Concepts and formulas to use  

We need to conduct a hypothesis in order to test the claim that the true proportion is higher than 0.5:  

Null hypothesis:[tex]p \leq 0.5[/tex]  

Alternative hypothesis:[tex]p > 0.5[/tex]  

When we conduct a proportion test we need to use the z statistic, 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].

Calculate the statistic  

Since we have all the info required we can replace in formula (1) like this:  

[tex]z=\frac{0.54 -0.5}{\sqrt{\frac{0.5(1-0.5)}{1000}}}=2.530[/tex]  

Statistical decision  

It's important to refresh the p value method or p value approach . "This method is about 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.  

The next step would be calculate the p value for this test.  

Since is a right tailed test the p value would be:  

[tex]p_v =P(z>2.530)=0.0057[/tex]  

Which function does a criminologist perform?

Answers

Answer:

To find why the crimes were committed

Evaluate 6.5b - 12.03 when b= 3​

Answers

Answer:

7.47

Step-by-step explanation:

6.5b - 12.03

Let b=3

6.5(3) - 12.03

Multiply first

19.5 - 12.03

7.47

Hi I think your answer is - 5.5

6.5b b=3. So you replace B with 3 and that makes it 6.53-12.03.

wich gives you - 5.5.

To avoid a service​ fee, your checking account balance must be at least ​$300 at the end of each month. Your current balance is ​$337.03. You use your debit card to spend ​$132.78. What possible amounts can you deposit into your account by the end of the month to avoid paying the service​ fee?

Answers

A deposit of at least $95.75 is needed to avoid the service fee, as this will bring the balance from $204.25 back to the required $300 minimum.

To avoid a service fee, we need to ensure that the checking account balance is at least $300 at the end of the month. Starting with a balance of $337.03 and after spending $132.78, the new balance is calculated as follows:

$337.03 - $132.78 = $204.25.

To avoid the service fee, the account balance must return to at least $300. Therefore, you need to deposit the difference between your current balance and the minimum balance required:

$300 - $204.25 = $95.75.

Any deposit amount greater than or equal to $95.75 will therefore avoid the service fee.

Please help me in don't understand how to do this

Answers

Answer:

36

Step-by-step explanation:

[tex] \frac{c}{4} - 5 = 4 \\ \\ \frac{c}{4} = 4 + 5\\ \\ \frac{c}{4} = 9 \\ \\ c = 9 \times 4 \\ \\ \huge \red{ \boxed{ c = 36}}[/tex]

What does the confidence interval tell about the population of all adult​ females? Select the correct choice below​ and, if​ necessary, fill in the answer​ box(es) to complete your choice. A. We are 90​% confident that the interval from nothing to nothing actually contains the true mean attractiveness rating of all adult females. ​(Round to one decimal place as​ needed.) B. We are confident that 90​% of all adult females have attractiveness ratings between nothing and nothing. ​(Round to one decimal place as​ needed.) C. The results tell nothing about the population of all adult​ females, because participants in speed dating are not a representative sample of the population of all adult females.

Answers

Answer:

A. We are 90% confident that the interval from nothing to nothing actually contains true mean attractiveness rating of all adult females.

Step-by-step explanation:

The population is set of items which are similar in nature and that are to be observed for an outcome. The Confidence Interval is a defined probability that the parameters lies in this range. Population parameter is quantity which enters in probability distribution of random variable. In the given question the confidence interval is 90% which means the parameters lies within this range.

An aerosol can contains gases under a pressure

of 4.5 atm at 24 ◦C. If the can is left on a

hot sandy beach, the pressure of the gases

increases to 4.66 atm. What is the Celsius

temperature on the beach?

Answers

Answer:

temperature on the beach = T2 = 34.56 °C

Step-by-step explanation:

We are given;

P1 = 4.5 atm

T1 = 24 °C = 24 + 273 = 297 K

P2 = 4.66 atm

Thus, P1/T1 = P2 /T2

So, T2 = P2•T1/P1

Thus, T2 = (4.66x 297)/4.5

T2 = 307.56 K

Let's convert to °C to obtain ;

T2 = 307.56 - 273

T2 = 34.56 °C

Brooklyn bought 1 pound of cucumbers for a salad. She bought twice as much lettuce. How many ounces of lettuce did Brooklyn buy for the salad.

Answers

Answer:

32 ounces

Step-by-step explanation:

She bought 1 cucumber. She bought twice as much lettuce.

1(2) = 2 lbs of lettuce.

There are 16 ounces to the lb.

2 (16 ounces) = 32 ounces

Answer:

She bought 32 oz of lettuce.

Step-by-step explanation:

There are 16 oz in 1 lb. twice as much means 2x. 2 x 16 = 32.

simplified expression -6x+2/3(9-15x)-2

Answers

Answer:

-16x+4

Step-by-step explanation:

-6x+2/3(9-15x)-2

Distribute

-6x +2/3 *9 +2/3*(-15x) -2

-6x +6 -10x -2

Combine like terms

-6x-10x +6-2

-16x+4

Standardization of a Normal Distribution: Bryce reads in the latest issue of Pigskin Roundup that the average number of rushing yards per game by NCAA Division II starting running backs is 50 with a standard deviation of 8 yards. If the number of yards per game (X) is normally distributed, what is the probability that a randomly selected running back has 64 or fewer rushing yards

Answers

Answer:

[tex]P(X<64)=P(\frac{X-\mu}{\sigma}<\frac{64-\mu}{\sigma})=P(Z<\frac{64-50}{8})=P(z<1.75)[/tex]

And we can find this probability using the normal standard table or excel and we got:

[tex]P(z<1.75)=0.9599[/tex]

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".  

Solution to the problem

Let X the random variable that represent the number of rushing yards of a population, and for this case we know the distribution for X is given by:

[tex]X \sim N(50,8)[/tex]  

Where [tex]\mu=50[/tex] and [tex]\sigma=8[/tex]

We are interested on this probability

[tex]P(X<64)[/tex]

And the best way to solve this problem is using the normal standard distribution and the z score given by:

[tex]z=\frac{x-\mu}{\sigma}[/tex]

If we apply this formula to our probability we got this:

[tex]P(X<64)=P(\frac{X-\mu}{\sigma}<\frac{64-\mu}{\sigma})=P(Z<\frac{64-50}{8})=P(z<1.75)[/tex]

And we can find this probability using the normal standard table or excel and we got:

[tex]P(z<1.75)=0.9599[/tex]

An angle measures 48° more than the measure of its supplementary angle. What is the measure of each angle?

Answers

Answer:

66 and 114 degrees

Step-by-step explanation:

Supplementary angles add to 180 degrees.

An angle measures 48 more than its supplementary angle. If the supplementary angle is x, then the other angle must be x+48

x+x+48=180

Subtract 48 from both sides

x+x+48-48=180-48

x+x=132

Combine like terms

2x=132

Divide both sides by 2

2x/2=132/2

x=66

So, one of the angles is 66 degrees. The other is x+48

x+48

66+48=114

One of the angles is 66 degrees, the other is 114 degrees

Answer:

96

Step-by-step explanation:

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