The​ quality-control manager at a compact fluorescent light bulb​ (CFL) factory needs to determine whether the mean life of a large shipment of CFLs is equal to 7 comma 5137,513 hours. The population standard deviation is 1 comma 080 hours1,080 hours. A random sample of 8181 light bulbs indicates a sample mean life of 7 comma 2137,213 hours. a. At the 0.050.05 level of​ significance, is there evidence that the mean life is different from 7 comma 513 hours question mark7,513 hours? b. Compute the​ p-value and interpret its meaning. c. Construct a 9595​% confidence interval estimate of the population mean life of the light bulbs. d. Compare the results of​ (a) and​ (c). What conclusions do you​ reach?

Answers

Answer 1

Answer:

Step-by-step explanation:

We would set up the hypothesis test. This is a test of a single population mean since we are dealing with mean

For the null hypothesis,

µ = 7463

For the alternative hypothesis,

µ ≠ 7463

This is a 2 tailed test

Since the population standard deviation is given, z score would be determined from the normal distribution table. The formula is

z = (x - µ)/(σ/√n)

Where

x = sample mean

µ = population mean

σ = population standard deviation

n = number of samples

From the information given,

µ = 7463 hours

x = 7163 hours

σ = 1080 hours

n = 81

b) z = (7163 - 7463)/(1080/√81) = - 2.5

Looking at the normal distribution table, the probability corresponding to the z score is 0.02

Recall, population mean is 7463

The difference between sample sample mean and population mean is 7463 - 7163 = 300

Since the curve is symmetrical and it is a two tailed test, the x value for the left tail is 7463 - 300 = 7163

the x value for the right tail is 7463 + 300 = 7763

These means are higher and lower than the null mean. Thus, they are evidence in favour of the alternative hypothesis. We will look at the area in both tails. Since it is showing in one tail only, we would double the area. We already got the area below z as 0.02

We would double this area to include the area in the right tail of z = 2.5. Thus

p = 0.02 × 2 = 0.04

It means that in a sample of size 81 light bulbs, we would observe a sample mean of 300 hours or more away from 7463 about 4% of the time by chance alone.

c) Confidence interval is written in the form,

(Sample mean - margin of error, sample mean + margin of error)

The sample mean, x is the point estimate for the population mean.

Margin of error = z × σ/√n

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

α = 1 - 0.95 = 0.05

α/2 = 0.05/2 = 0.025

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

1 - 0.025 = 0.975

The z score corresponding to the area on the z table is 1.96. Thus, z score for 95% confidence level is 1.96

Margin of error = 1.96 × 1080/√81

= 235.2

Confidence interval = 7163 ± 23.2

a) Since alpha, 0.05 > than the p value, 0.04, then we would reject the null hypothesis. Therefore, at a 5% level of significance, there is evidence that the mean life is different from 7463 hours

Comparing the results of a and c, it is true that the population mean life is not 7463 hours.


Related Questions

Kings Department Store has 625 rubies, 800 diamonds, and 700 emeralds from which they will make bracelets and necklaces that they have advertised in their Christmas brochure. Each of the rubies is approximately the same size and shape as the diamonds and the emeralds. Kings will sell each bracelet for $400 and it costs them $150 to make it. Each bracelet is made with 2 rubies, 3 diamonds, and 4 emeralds. Kings will sell each necklace for $700 and it costs them $200 to make it. Each neckalce is made with 5 rubies, 7 diamonds, and 3 emeralds. a) Formulate the above problem as a Linear Programming problem with the objective of maximizing profit

Answers

Step-by-step explanation:

Let Xb be the no of braclets made

Let Xn be the no of necklaces made

Max Z=250Xb + 500Xn (Objective Function)

Subject to

2Xb + 5Xn <= 625 (rubies)

3Xb + 7 Xn <= 800 ( diamonds)

4Xb + 3 Xn <= 700 (Emeralds)

Xb>=0 (non-negativity)

Xn >= 0 (non negativity

Answer:

Step-by-step explanation:

We are to Formulate the question given as a Linear Programming problem with the objective of maximizing profit.

From the question;

Kings will sell each bracelet for $400 and it costs them $150 to make it.

This implies that; King will net a profit on $250 on each bracelet made with 2 rubies, 3 diamonds, and 4 emeralds :

Also;

Kings will sell each necklace for $700 and it costs them $200 to make it

i.e King will net a profit of $500 on each necklace  made with 5 rubies, 7 diamonds, and 3 emeralds.

Now; let's assume that :

[tex]Y_{br}[/tex]  be the no of bracelets made ;   &

[tex]Y_{nk}[/tex]  be the no of necklaces made

[tex]\\ \\Max \ Z=250 \ Y{_b_r}} + 500 \ Y{_n_k}[/tex]    (Objective Function)

Subject to :

[tex]2 \ Y_{br} + 5 \ Y_{nk}[/tex] ← 625 (rubies)

[tex]3 \ Y_{br} + 7 \ Y_{nk}[/tex] ← 800 ( diamonds)

[tex]4 \ Y_{br} + 3 \ Y_{nk}[/tex] ← 700 (Emeralds)

[tex]\\ \\Y_{br} \\[/tex] ⇒ 0 (non-negativity)

[tex]\\\\ \ Y_{nk}\\[/tex] ⇒ 0 (non negativity)















Write the word sentence as an equation. Then solve the equation.

10 more than a number c is 3

Answers

Answer:

Equation: 10+c=3

Answer: c=-7

Step-by-step explanation:

1. 10+c=3

2. c=3-10

3. c=-7

Answer:

c=-7

Step-by-step explanation:

c+10=3

Subtract 10 from both sides

c=-7

3/4(1440) + 295.25 + (-33.50)

Answers

Answer:

Your answer is 1341.75

Step-by-step explanation:

3/4 x 1440 = 1080

1080 + 295.25 = 1375.25

1375.25 + -33.50 = 1341.75

The solution of the given expression 3/4(1440) + 295.25 + (-33.50) involving multiplication, addition, and subtraction in mathematics is equal to 1341.75.

The expression provided is:

3/4(1440) + 295.25 + (-33.50)

To solve this, we need to follow the order of operations (PEMDAS):

Multiply 3/4 by 1440 to get 1080.

Add 1080 to 295.25 to get 1375.25.

Finally, subtract 33.50 from 1375.25 to get the final answer of 1341.75.

On a recent Saturday, a total of 1086 people visited a local library. Of these people, 269 were under age 10, 466 were aged 10–18, 185 were aged 19–30, and the rest were more than 30 years old. One person is sampled at random. What is the probability that the person is more than 30 years old?

Answers

Answer:

The probability that the person is more than 30 years old is 0.153

Step-by-step explanation:

We can obtain the probability that the person sampled is more than 30 years old by dividing the amount of peope with more than 30 years old with the total amount of people that visited the library that Saturday, in other owrds, 1086.

The number of people with more than 30 years old can be obtained by substracting from 1086 (the total amount) the total amount of people with 30 years or less.

There are 269 (under 10) + 466 (between 10 and 18) + 185 (between 19 and 30) = 920 people under 30 years old. Therefore, the total amount of people with more than 30 years old is 1086-920 = 166, and the probability that a person selected is from that group is 166/1086 = 0.153

Jimmy is a flag person and earned $321.10 last week for 32.5 hours work. What is his hourly wage? *
Your answer

Answers

The answer should be 9.88

What is inequality for 48-15=

Answers

Answer:

48-15 is 33

Step-by-step explanation:

Can someone explain this please???

Answers

A function is a rule that assigns exactly one output to a given input. The input is taken from a set called the domain, and the corresponding output belongs to a set called the range.

1. In this exercise, we're calling the pool of patients 1-8 the domain, and the pool of nurses A-D the range. The given table describes a function because any patient is assigned to only one nurse.

2. This wouldn't be a function if at least one patient was assigned to more than one nurse. If this were to happen in practice, the patient could be, say, given the same dose of some medicine twice if the nurses aren't careful.

3. Making the nurse pool the domain and the patient pool the range would give a relation that is not a function, since more than one patient is assigned to one nurse.

What's the answer to 1/2(x+4)^2-5+=3.

Answers

Answer:

x = 0

Step-by-step explanation:

To solve this equation you would need to get x by itself on one side

1/2 (x+4)^2 - 5 = 3

1.) add 5 to both sides

1/2 (x+4)^2 = 8

2.) divide each side by 1/2

(x+4)^2 = 16

3.) find the square root of both sides

(x+4) = 4

4.) subtract 4 from both sides

x = 0

The app "Photomath" is a great way to solve problems like these and it gives a step by step explanation that might be easier to understand than mine :)

Amara needs 454545 kilograms of meat to feed her 222 pet dragons each day. Each pet dragon eats the same amount of meat.

Answers

Answer:

2047.5 kg

Step-by-step explanation:

There's a total of 454545 kg of meat, and each dragon gets x kg. There are 222 dragons. So, we have the equation: 222x = 454545

Divide by 222 from both sides: x = 2047.5 kg

Thus, each dragon gets 2047.5 kg of meat.

Hope this helps!

It is recommended that adults get 8 hours of sleep each night. A researcher hypothesized college students got less than the recommended number of hours of sleep each​ night, on average. The researcher randomly sampled 20 college students and calculated a sample mean of 7.5 hours per night. If the researcher wanted to perform a​ one-sample t-test, which of the following is a correct​ statement?

A: By taking a random​ sample, the researcher has guaranteed that the distribution of number of hours of sleep per night for all college students is normal.
B.The number of hours of sleep per night for all college students must be normally distributed because the sample size is small.
C.By taking a random​ sample, the researcher has guaranteed that the distribution of sample means is normal.
D.The distribution of sample means will be normal even if the distribution of the data in the population is not normal.

Answers

Final answer:

In a one-sample t-test, the normal distribution of sample means is more important than the normality of individual data in the population. This follows the Central Limit Theorem which states that, with a decently large sample size, the distribution of sample means will approach normality regardless of the population distribution.

Explanation:

Statement C is the correct option. The Central Limit Theorem indicates that regardless of the population distribution, as long as we have a sufficiently large sample size, the sample means will be approximately normally distributed. However, this doesn't guarantee that the distribution of the individual data (the number of sleep hours) in the population is normal.

It’s important to note two things: First, the idea of random sampling is to avoid bias and to have a representative sample of the population under study. Second, the rule of thumb is that the sample size should be approximately 30 or greater for the Central Limit Theorem to take effect, to provide a decent approximation of a normal distribution of sample means. In this instance, a sample size of 20 is close to 30, so we may anticipate that the sample mean distribution is roughly normal.

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In 10-mph crash tests, 25% of a certain type of automobile sustain no visible damage. A modified bumper design has been proposed in an effort to increase this percentage. Let denote the proportion of all cars with this new bumper that sustain no visible damage in 10-mph crash test. The hypothesis to be tested is The test will be based on an experiment involving independent crashes of car prototypes with the new bumper. Let denote the number of crashes resulting in no visible damage, and consider the test procedure that rejects

(a) Find the probability of type I error.

Answers

Answer:

(a) Find the probability of type I error. = 0.1018

Step-by-step explanation:

check attachment for the answer

Answer:

The probability of Type I error is = 0.10185.

Step-by-step explanation:

Solution:-

The type I - error is defined as the probability of rejecting Null hypothesis defined by Alternate hypothesis:

                          Ha : X ≥ 8

Where,

X : Denote the number of cars crash with no visible damage

The random variate "X" is defined by binomial distribution:

                            X ~ B ( n = 20 , p = 0.25 )

- The probability of Type I error:

                        P (Type I error ) = P ( Reject Null hypothesis )

                                                   = P ( X ≥ 8 )

- The probability mass function of binomial random variate "X" is given:

                     [tex]P ( X = x ) = nCr (p)^r * (1-p)^(^n^-^r^)\\P ( X \geq 8 ) = 1 - P ( X < 8 )\\\\P ( X \geq 8 ) = 1 - [ P ( X = 0 ) + P ( X = 1 ) + P ( X = 2 ) + P ( X = 3 ) + P ( X = 4 ) + P ( X = 5 ) + P ( X = 6 ) + P ( X = 7 ) ][/tex][tex]P ( X \geq 8 ) = 1 - [ (0.75)^2^0 + 20(0.25)*(0.75)^1^9 + 20C2(0.25)^2*(0.75)^1^8 +\\\\ 20C3(0.25)^3*(0.75)^1^7 + 20C4(0.25)^4*(0.75)^1^6 + 20C5(0.25)^5*(0.75)^1^5\\\\ + 20C6(0.25)^6*(0.75)^1^4 + 20C7(0.25)^7*(0.75)^1^3 ] \\\\\\P ( X \geq 8 ) = 1 - [ 0.00317 + 0.02114 + 0.06694 + 0.13389 + 0.18968 + 0.20233\\\\+ 0.16860 + 0.11240]\\\\P ( X \geq 8 ) = 1 - 0.89815 = 0.10185[/tex]

Answer: The probability of Type I error is = 0.10185.

Many investors and financial analysts believe the Dow Jones Industrial Average (DJIA) provides a good barometer of the overall stock market. On January 31, 2006, 9 of the 30 stocks making up the DJIA increased in price (The Wall Street Journal, February 1, 2006). On the basis of this fact, a financial analyst claims we can assume that 30% of the stocks traded on the New York Stock Exchange (NYSE) went up the same day.
1. Formulate null and alternative hypotheses to test the analyst's claim.
H0: p
Ha: p
2. A sample of 50 stocks traded on the NYSE that day showed that 24 went up. What is your point estimate of the population proportion of stocks that went up (to 2 decimals)?
3. Conduct your hypothesis test using = .01 as the level of significance.
Calculate the value of the test statistic (to 2 decimals).
What is the p-value (to 4 decimals)?
Can you conclude that the proportion of stocks going up is not .30?

Answers

Answer:

1) H0: p=0.3

Ha: p≠0.3

2) 0.48

3)•2.78

•0.0054. So, we reject H0.

• No, we cannot conclude

Step-by-step explanation:

1) To formulate the null and alternative hypothesis:

• Null hypothesis:

[tex] H_0: p=0.3 [/tex]

•Alternative hypothesis:

Ha: p≠0.3

2) Point estimate of the population proportion stocks that went up:

Since sample is 50 stocks and 24 went up, we have phat as:

[tex]phat = \frac{24}{50} = 0.48[/tex]

3) • Hypothesis test using 0.01 as level of significance:

Test statistic =

[tex] Z = \frac{phat-p}{\sqrt{\frac{p*(1-p)}{n}}}[/tex]

[tex] = \frac{0.48-0.3}{\sqrt{\frac{0.3*0.7}{50}}}[/tex]

= 2.78

•Using standard normal table

P value =

2*(P>2.78) = 0.0054

• The p value (0.0054) is less than level of significance (0.01), we reject null hypothesis H0.

• No, we cannot conclude that the proportion of stocks going up is not .30

The distance from Parrot Point Airport to the Ivy Cliffs is 172 miles at and angle of 7.0 degrees northeast. There is a wind blowing southeast at 25 miles per hour. You want to make this trip in 2 hours by flying straight there. At what speed* and heading should you fly?

Answers

Answer:

Speed = x/t = 146.61/2 = 73.30 mph

direction y = 22.59° northeast

Step-by-step explanation:

Given;

The distance from Parrot Point Airport to the Ivy Cliffs is 172 miles at and angle of 7.0 degrees northeast;

Resultant distance R = 172 (7° northeast)

Time given to make the trip t = 2 hours

Distance moved by wind during the time dw = 25×2 = 50 miles south east.

Let x represent the distance covered by plane without wind during the time and y the direction;

Resolving into horizontal and vertical component;

horizontal;

x cosy + 50cos45 = 172cos7

xcosy = 172cos7 - 50cos45 .....1

Vertical;

xsiny - 50sin45 = 172sin7

xsiny = 172sin7 + 50sin45 .....2

Divide equation 2 by 1

xsiny/xcosy = (172sin7 + 50sin45)/(172cos7 - 50cos45)

tany = 0.4160

y = taninverse (0.4160)

y = 22.59° northeast

Substituting y into equation 2;

xsin22.59 = 172sin7 + 50sin45

x = (172sin7 + 50sin45)/sin22.59

x = 146.61 miles

Speed = x/t = 146.61/2 = 73.30 miles per hour

Speed = 73.30mph

Simplify the expression 13+(x+8)

Answers

Answer:x+21

Step-by-step explanation:

Calculate social security taxes

Answers

Answer:

there is no any number to caculate social security tax.

Step-by-step explanation:

Final answer:

Social Security taxes are calculated using a deduction rate of 6.2% and 1.45% for Medicare from an employee's gross annual income. Employers also contribute matching amounts. However, the economic impact of employers' contributions often invariably impact employees indirectly.

Explanation:

To calculate social security taxes, you need to consider a standard deduction rate of 6.2% for the Social Security and 1.45% from Medicare. These deductions are generally taken directly out of the employee's gross annual income. Employers also contribute matching percentages. However, it is important to note that in reality, the burden of the employer's contribution may in effect fall on the employee as it can result in lower wages. For instance, for those considered as independent contractors or members of the 'gig economy' receiving a 1099 tax statement, the individual must pay both the employer and employee portion of the social security and Medicare taxes.

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Someone please help, this is my last resort

Answers

Answer:

34 5/8

Step-by-step explanation:

you just add all the numbers on the left and the two drawer numbers then boom!!

A student wants to compare textbook prices for two online bookstores. She takes a random sample of five textbook titles from a list provided by her college bookstore, and then she determines the prices of those textbooks at each of the two websites. The prices of the five textbooks selected are listed below in the same order for each online bookstore. A: $115, $43, $99, $80, $119 B: $110, $40, $99, $69, $109 (a) Are these independent or dependent samples

Answers

Answer:

Dependent sample: The same textbook are being compared.

Step-by-step explanation:

We are given the following in the question:

A student wants to compare textbook prices for two online bookstores.

Sample 1 from bookstore A:

$115, $43, $99, $80, $119

Sample 2 from bookstore B:

$110, $40, $99, $69, $109

Dependent and independent sample:

Dependent samples are paired observations for same set of items.Independent samples are observations made on two different sets of items.If the values in one sample affect the observations in the other sample, then the samples are dependent.If the values in one sample have no effect about those of the other sample, then the samples are independent.

Thus, the given sample is dependent sample as the same textbook is being compared from two different bookstore.

Final answer:

The textbook prices listed for the two different online bookstores are dependent samples, as the prices are paired for the same textbooks across the two bookstores. Analyzing this data would involve using statistical methods suitable for dependent samples, like paired t-tests.

Explanation:

The textbook prices listed by the student for the two different online bookstores represent dependent samples. This is because the prices are paired for the same textbooks across the two bookstores. They are not independent samples because the price of a given book in one store could potentially influence the price of the same book in the other store. For example, if one store lowers its prices, the other might follow suit to remain competitive.

Consideration of such data requires the analysis method suitable for dependent samples. Specifically, using methodologies like paired t-tests in statistics might be appropriate in this scenario to compare the prices from the different online bookstores. These methods account for the fact that measurements within each pair could be correlated.

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Suppose that f (400 )equals3000 and f prime (400 )equals10. Estimate each of the following. ​(a) f (401 )​(b) f (400.5 )​(c) f (399 )​(d) f (398 )​(e) f (399.75 )

Answers

Answer:

a) [tex]f(401) = 3010[/tex], b) [tex]f(400.5) = 3005[/tex], c) [tex]f(399) = 2990[/tex], d) [tex]f(398) = 2980[/tex], e) [tex]f(399.75) = 2997.5[/tex]

Step-by-step explanation:

The estimation of each value can be found by the following value:

[tex]f(x + \Delta x) = f(x) + f'(x)\cdot \Delta x[/tex]

a) [tex]f(401) = 3000 + 10\cdot (401-400)[/tex]

[tex]f(401) = 3010[/tex]

b) [tex]f(400.5) = 3000 + 10\cdot (400.5 - 400)[/tex]

[tex]f(400.5) = 3005[/tex]

c) [tex]f(399) = 3000 + 10\cdot (399 - 400)[/tex]

[tex]f(399) = 2990[/tex]

d) [tex]f(398) = 3000 + 10\cdot (398-400)[/tex]

[tex]f(398) = 2980[/tex]

e) [tex]f(399.75) = 3000 + 10\cdot (399.75-400)[/tex]

[tex]f(399.75) = 2997.5[/tex]

Which events have a probability of 25 percent? Select three options.
choosing a green jelly bean out of a bag that contains 2 green jelly beans, 1 red jelly bean, and 5 yellow jelly beans
rolling a number less than 3 on a six-sided die
spinning a number less than 2 on a spinner that has four equal sections numbered from 1 to 4
choosing an Oregon state quarter out a bag that contains 4 California state quarters, 3 Oregon state quarters, 6 Texas state quarters, and 3 New York state quarters
choosing a spade out of a standard deck of cards that contains 13 hearts, 13 clubs, 13 diamonds, and 13 spades

Answers

Choosing a green jelly bean.

Spinning a number less than 2 on a spinner.

Choosing a spade out of a standard deck of cards.

What are the probabilities?

Probability determines the chances that an event would happen. The probability the event occurs is 1 and the probability that the event does not occur is 0.

Probability of choosing a green jelly bean = number of green jelly bean / total number of beans

2/8 x 100 = 25%

Probability of spinning a number less than 2 on a spinner = number that is less than 2 / total number of sections

1/4 x 100 = 25%

Probability of choosing a choosing a spade= number of spade / total cards in the deck

13/54 x 100 = 25%

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The three options that have a probability of 25 percent are:

- Choosing a green jelly bean

- Spinning a number less than 2 on a spinner

- Choosing a spade from a standard deck of cards

The probability of an event occurring is calculated by dividing the number of favorable outcomes by the total number of possible outcomes. A probability of 25 percent corresponds to a ratio of 1 out of 4 (since 25% is one-fourth of 100%). Let's analyze the options:

1. Choosing a green jelly bean: There are 2 green jelly beans out of a total of 2 + 1 + 5 = 8 jelly beans. The probability is 2/8, which simplifies to 1/4 or 25%. This option has a probability of 25%.

2. Rolling a number less than 3 on a six-sided die: There are 2 favorable outcomes (1 and 2) out of 6 possible outcomes (1 through 6). The probability is 2/6, which simplifies to 1/3 or approximately 33.33%. This option does not have a probability of 25%.

3. Spinning a number less than 2 on a spinner: There is 1 favorable outcome (1) out of 4 possible outcomes (1 through 4). The probability is 1/4 or 25%. This option has a probability of 25%.

4. Choosing an Oregon state quarter: There are 3 Oregon state quarters out of a total of 4 + 3 + 6 + 3 = 16 state quarters. The probability is 3/16, which is not equal to 25%.

5. Choosing a spade from a standard deck of cards: There are 13 spades out of a total of 13 + 13 + 13 + 13 = 52 cards. The probability is 13/52, which simplifies to 1/4 or 25%. This option has a probability of 25%.

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Which expression is equivalent to:
16(w+q)
A. (m + 16) (w + 16) B.16w + 169
C. 16w +9
D. W + 169

Answers

Final answer:

The equivalent expression to 16(w+q) is 16w + 16q, but none of the given options A, B, C, or D are correct as they do not accurately represent this distribution. The closest option would be C (16w + 9), though it is still incorrect because it has 9 instead of 16q.

Explanation:

The question asks which expression is equivalent to 16(w+q). The correct way to distribute a constant over a sum inside parentheses is to multiply each term inside the parentheses by that constant. So, 16 must be multiplied by both w and q.

Therefore, the equivalent expression is 16w + 16q. Looking at the provided options:

A. (m + 16) (w + 16) includes additional terms and multiplication not present in the original expression.B. 16w + 169 includes the term 169, which is not correct since no such number results from multiplying 16 by q.C. 16w + 16q is correct, but as given in the option just as 16w + 9 it is incorrect because it has 9 instead of 16q.D. w + 169 does not multiply w by 16 and includes the incorrect number 169.

Since none of the given options are exactly 16w + 16q, no available option is a correct equivalent expression to 16(w+q).

A​ half-century ago, the mean height of women in a particular country in their 20s was 64.7 inches. Assume that the heights of​ today's women in their 20s are approximately normally distributed with a standard deviation of 2.07 inches. If the mean height today is the same as that of a​ half-century ago, what percentage of all samples of 21 of​ today's women in their 20s have mean heights of at least 65.86 ​inches?

Answers

Answer:

99.5% of all samples of 21 of​ today's women in their 20's have mean heights of at least 65.86 ​inches.

Step-by-step explanation:

We are given that a half-century ago, the mean height of women in a particular country in their 20's was 64.7 inches. Assume that the heights of​ today's women in their 20's are approximately normally distributed with a standard deviation of 2.07 inches.

Also, a samples of 21 of​ today's women in their 20's have been taken.

Let [tex]\bar X[/tex] = sample mean heights

The z-score probability distribution for sample mean is given by;

                          Z = [tex]\frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n} } }[/tex] ~ N(0,1)

where, [tex]\mu[/tex] = population mean height of women = 64.7 inches

            [tex]\sigma[/tex] = standard deviation = 2.07 inches

The Z-score measures how many standard deviations the measure is away from the mean. After finding the Z-score, we look at the z-score table and find the p-value (area) associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X.

Now, Probability that the sample of 21 of​ today's women in their 20's have mean heights of at least 65.86 ​inches is given by = P([tex]\bar X[/tex] [tex]\geq[/tex] 65.86 inches)

  P([tex]\bar X[/tex] [tex]\geq[/tex] 65.86 inches) = P( [tex]\frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n} } }[/tex] [tex]\geq[/tex] [tex]\frac{65.86-64.7}{\frac{2.07}{\sqrt{21} } }[/tex] ) = P(Z [tex]\geq[/tex] -2.57) = P(Z [tex]\leq[/tex] 2.57)

                                                                        = 0.99492  or  99.5%

The above probability is calculated by looking at the value of x = 2.57 in the z table which has an area of 0.99492.

Therefore, 99.5% of all samples of 21 of​ today's women in their 20's have mean heights of at least 65.86 ​inches.

A review of 200 days-away-from-work injuries for a large, multi-facility corporation was conducted, and it was determined that 18 of them were due to lower back injuries. Only 14.3 were expected under normal conditions. The rest of the injuries were due to other causes where 185.7 were expected. What is the chi-square value? Discuss whether there was a significant difference in observed data vs. the expected data. Also, discuss how the process of hypothesis testing might prove helpful to the safety professional.

Answers

Answer:

a) Chi square value = 1.031

b) There is no significant difference between the observed and expected values.

c) Check explanations for the part C of the question

Step-by-step explanation:

a) People away from work due to lower back injuries:

Observed value = 18

Expected value = 14.3

People away from work due to other injuries:

Observed value = 200 - 18 = 182

Expected value = 185.7

The chi square value is calculated by the formula:

[tex]x^{2} = \frac{(O-E)^{2} }{E}[/tex]

For people out of work due to lower back injuries:

Chi square value,

[tex]x^{2} = \frac{(18-14.3)^{2} }{14.3} \\x^{2} = 0.957[/tex]

For people out of work due to other injuries:

Chi square value,

[tex]x^{2} = \frac{(182-185.7)^{2} }{185.7} \\x^{2} = 0.074[/tex]

Total chi square value for the distribution:

[tex]x^{2} = 0.074 + 0.957\\x^{2} = 1.031[/tex]

b) The degree of freedom, df = n -1

n = 2 ( two categories of people are considered)

df = 2-1 = 1

For df = 1 and, chi square = 1.031

P - value = 0.3099

p- value = 0.3099, the result is not significant at p < 0.05

There is no significant difference between the observed and expected values.

c) Hypothesis testing helps the safety professionals to statistically analyse any situations and determine whether or not they are safe. It can help them to predict the outcome of a given situation by making necessary observations.

Use Definition 7.1.1, DEFINITION 7.1.1 Laplace Transform LetUse Definition 7.1.1, DEFINITION 7.1.1 Laplace Transform Let f be a function defined for t ≥ 0. Then the integral ℒ{f(t)} = [infinity] e−stf(t) dt 0 is said to be the Laplace transform of f, provided that the integral converges. to find ℒ{f(t)}. (Write your answer as a function of s.) WebAssign Plotf be a function defined for t ≥ 0. Then the integral ℒ{f(t)} = [infinity] e−stf(t) dt 0 is said to be the Laplace transform of f, provided that the integral converges. to find ℒ{f(t)}. (Write your answer as a function of s.) f(t) = cos(t), 0 ≤ t < π 0, t ≥ π

Answers

Answer:

[tex]F(s) = \frac{s(e^{\pi s}+1)}{s^2 +1}[/tex]

Step-by-step explanation:

Using the formula for Laplace the transformations if [tex]F(s)[/tex]  is the converted function then

[tex]F(s) = \int\limits_{0}^{\infty} e^{-st} \cos(t) dt = \int\limits_{0}^{\pi} e^{-st} \cos(t) dt[/tex]

To solve that integral you need to use integration by parts, when you do integration by parts you get that

[tex]F(s) = \frac{s(e^{\pi s}+1)}{s^2 +1}[/tex].

Answer:

The laplace transform is [tex] F(s) = \frac{s(1+e^{-s\pi})}{s^2+1}[/tex]

Step-by-step explanation:

Let us asume that f(t) =0 for t<0. So, by definition, the laplace transform is given by:

[tex]I = \int_{0}^\pi e^{-st}\cos(t) dt[/tex]

To solve this integral, we will use integration by parts. Let u= cos(t)  and dv = [tex]e^{-st}[/tex], so v=[tex]\frac{-e^{st}}{s}[/tex] and du = -sin(t), then, in one step of the integration we have that

[tex]I = \left.\frac{-\cos(t) e^{-st}}{s}\right|_{0}^\pi- \int_{0}^\pi \frac{\sin(t) e^{-st}}{s} dt[/tex]

Let [tex] I_2 = \int_{0}^\pi \frac{\sin(t) e^{-st}}{s} dt[/tex]. We will integrate I_2 again by parts. Choose u = sin(t) and dv = [tex]\frac{e^{-st}}{s}[/tex]. So

[tex] I_2 = \left.\frac{-\sin(t) e^{-st}}{s^2}\right|_{0}^\pi + \int_{0}^\pi \frac{\cos(t) e^{-st}}{s^2}dt [/tex]

Therefore,

[tex]I = \left.\frac{-\cos(t) e^{-st}}{s}\right|_{0}^\pi - (\left.\frac{-\sin(t) e^{-st}}{s^2}\right|_{0}^\pi - \frac{1}{s^2} I[/tex]

which is an equation for the variabl I. Solving for I we have that

[tex]I(\frac{s^2+1}{s^2}) =\left.\frac{-\cos(t) e^{-st}}{s}\right|_{0}^\pi+\left.\frac{\sin(t) e^{-st}}{s^2}\right|_{0}^\pi[/tex]

Then,

[tex]I = \left.\frac{-s\cos(t) e^{-st}}{s^2+1}\right|_{0}^\pi+\left.\frac{\sin(t) e^{-st}}{s^2+1}\right|_{0}^\pi[/tex].

Note that since the sine function is 0 at 0 and pi, we must only care on the first term. Then

[tex]I = \left.\frac{-s\cos(t) e^{-st}}{s^2+1}\right|_{0}^\pi = \frac{s}{s^2+1}(1-(-1)e^{-s\pi}} = \frac{s(1+e^{-s\pi})}{s^2+1}[/tex]

Find the percentage of people in the sample who prefer blue.

Answers

There is no sample given, please provide us with an attachment for your answer.

There’s no picture....what am I answering??

Hi I need help with this, I am very confused

Answers

Answer:

1/81

Step-by-step explanation:

P(1st ticket is a winner) = 1/9

These are independent events

P(2nd ticket is a winner) = 1/9

P (winner, winner) = 1/9 * 1/9 = 1/81

I get HOW to make a box and whisker plot. What I don't get is WHY you would want to make one. From a practical point of view, what can it teach you?

Answers

Answer:

I'd say go to Wikipedia and look it up.  It is something that cannot be summarized into just a few words.

Step-by-step explanation:

Suppose you deposit $500 in a bank account that pays 8% annual simple
interest. Find the interest earned after 3 years.​

Answers

Answer:

120

Step-by-step explanation:

I=prt . Where: P = Principal Amount; I = Interest Amount; r = Rate of Interest per year in decimal and time t should be in the same time units such as months or years.

I=500(.08)(3)

Answer:

8% of 500 is 40, For the first year is 540. 8% of 540 is 43.20 dollars. 8% of 583.2 is 46.656. So the total is 630 by rounding but the actual amount is 629.956. The interest is 129.956

P.S

Have an Amazing Day!

-Faker/Tosrel

select each angle that has a measure of 30

Answers

Answer:

Please post another question with the angle that you were given. Thank you!

Step-by-step explanation:

There wasn't any angles given therefore, I couldn't help!

You did not give out the angles

Lonnie has a shutter that is 4 yards, 17 inches long. How many inches long is Lonnie's shutter?

Answers

Answer:

161 inches

Step-by-step explanation:

This problem is all about conversion. How many feet are in a yard? 3. How many feet are in 4 yards? 12 feet. There are 12 inches in a foot. 12 feet means 12 x 12 inches, which is 144. 144 + the other 17 inches, is 161.

Answer:

The answer is into the unkown

Step-by-step explanation:

elsa and anna are good sisters olaf olaf anna fiftys ahdpnf3oehisklNHW3q3tsqagwgdraw4gw

Your boss tells you that she knows the length of the widgets your company makes is normally distributed with a mean of 25 inches and a population standard deviation of 12 inches. If you take samples of size 9 from finished widgets in the warehouse, in order to check for quality, what will be the mean and standard deviation of the sampling distribution?

Answers

Answer:

Mean of sampling distribution = 25 inches

Standard deviation of sampling distribution = 4 inches

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 25 inches

Standard Deviation, σ = 12 inches

Sample size, n = 9

We are given that the distribution of length of the widgets is a bell shaped distribution that is a normal distribution.

a) Mean of the sampling distribution

The best approximator for the mean of the sampling distribution is the population mean itself.

Thus, we can write:

[tex]\bar{x} = \mu = 25\text{ inches}[/tex]

b) Standard deviation of the sampling distribution

[tex]s = \dfrac{\sigma}{\sqrt{n}} = \dfrac{12}{\sqrt{9}} = 4\text{ inches}[/tex]

Using the Central Limit Theorem, it is found that:

The mean of the distribution would be of 25 inches.The standard deviation of the distribution would be of 4 inches.

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For the population:

Mean of 25 inches, thus [tex]\mu = 25[/tex]Standard deviation of 12 inches, thus [tex]\sigma = 12[/tex].

Samples of size 9, thus [tex]n = 9[/tex].

By the Central Limit Theorem:

The mean of the sampling distribution is [tex]\mu = 25[/tex].The standard deviation of the sampling distribution is [tex]s = \frac{\sigma}{\sqrt{n}} = \frac{12}{\sqrt{9}} = 4[/tex].

A similar problem is given at https://brainly.com/question/15519778

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