Question 1

A pharmaceutical company manufactures a 81-mg pain reliever. Company specifications include that thestandard deviation of the amount of the active ingredient must not exceed 2 mg. The quality -control managerselects a random sample of 30 tablets from a certain batch and finds that the standard deviation is 2.4 mg.Assume that the amount of the active ingredient is normally distributed. Test the claim that the standarddeviation of the amount of the active ingredient is greater than 2 mg at the α = 0.05 level of significance.

Accepted Answer

The answer of A pharmaceutical company manufactures a 81-mg pain...

Question 2

The mean utility bill in one city during the summer was less than $90. Write the null and alternativehypotheses.

Accepted Answer

The answer of The mean utility bill in one city...

Question 3

Test the claim that  Assume that the population is normally distributed.

Accepted Answer

The answer of Test the claim that  Assume that...

Question 4

Test the claim that  Assume that the population is normally distributed.

Accepted Answer

The answer of Test the claim that  Assume that...

Question 5

A local tennis pro-shop strings tennis rackets at the tension (pounds per square inch) requested by thecustomer. Recently a customer made a claim that the pro-shop consistently strings rackets at lower tensions, onaverage, than requested. To support this claim, the customer asked the pro shop to string 13 new rackets at 65psi. Suppose the two-tailed P-value for the test described above (obtained from a computer printout) is 0.09.Give the proper conclusion for the test. Use α = 0.05.

Accepted Answer

A)  There is sufficient evidence to conclude that μ, the true mean tension of the rackets, is less than 65 psi. 
B)  Accept H0 and conclude that μ, the true mean tension of the rackets, equals 65 psi. 
C)  There is insufficient evidence to conclude that μ, the true mean tension of the rackets, is less than 65 psi. 
D)  Reject H0 and conclude that μ, the true mean tension of the rackets, equals 65 psi.

Question 6

A local eat-in pizza restaurant wants to investigate the possibility of starting to deliver pizzas. The owner ofthe store has determined that home delivery will be successful if the average time spent on the deliveries doesnot exceed 32 minutes. The owner has randomly selected 23 customers and has delivered pizzas to their homesin order to test if the mean delivery time actually exceeds 32 minutes. Suppose the P-value for the test wasfound to be 0.0297. State the correct conclusion.

Accepted Answer

A)  At $\alpha = 0.025$, we fail to reject $\mathrm { H } _ { 0 }$. 
B)  At $\alpha = 0.05$, we fail to reject $\mathrm { H } _ { 0 }$. 
C)  At $\alpha = 0.02$, we reject $\mathrm { H } _ { 0 }$. 
D)  At $\alpha = 0.03$, we fail to reject $\mathrm { H } _ { 0 }$.

Question 7

According to a national statistics bureau, 3.7% of males living in the Southwest were retired exterminators. Aresearcher believes that the percentage has increased since then. She randomly selects 250 males in theSouthwest and finds that 4 of them are retired exterminators. Test this researcherʹs claim at the α = 0.1 level ofsignificance.

Accepted Answer

The answer of According to a national statistics bureau, 3.7%...

Question 8

The mean annual return for an employeeʹs IRA is at most 3.4 percent. Write the null and alternativehypotheses.

Accepted Answer

The answer of The mean annual return for an employeeʹs...

Question 9

A method currently used by doctors to screen women for possible breast cancer fails to detect cancer in 15% ofthe women who actually have the disease. A new method has been developed that researchers hope will beable to detect cancer more accurately. A random sample of 70 women known to have breast cancer werescreened using the new method. Of these, the new method failed to detect cancer in 8. Calculate the teststatistic used by the researchers for this test of hypothesis. Round to the nearest thousandth.

Accepted Answer

The answer of A method currently used by doctors to...

Question 10

Find the standardized test statistic t for a sample with $$\mathrm { n } = 10 , \overline { \mathrm { x } } = 7.9 , \mathrm {~s} = 1.3 \text {, and } \alpha = 0.05 \text { if } \mathrm { H } _ { 0 } : \mu \geq 8.8 \text {. Round }$$ your answer to three decimal places.

Accepted Answer

A)  -2.189 
B)  -3.186 
C)  -3.010 
D)  -2.617

Question 11

True or False: Type I and Type II errors are independent events.

Accepted Answer

A) True 
 B)False

Question 12

Increasing numbers of businesses are offering child-care benefits for their workers. However, one union claimsthat more than 80% of firms in the manufacturing sector still do not offer any child-care benefits to theirworkers. A random sample of 390 manufacturing firms is selected and asked if they offer child-care benefits.Suppose the P-value for this test was reported to be p = 0.1112. State the conclusion of interest to the union.Use α = 0.10.

Accepted Answer

The answer of Increasing numbers of businesses are offering child-care...

Question 13

If we reject the null hypothesis when the null hypothesis is true, then we have made a

Accepted Answer

A)  Type I error 
B)  Type II error 
C)  Correct decision 
D)  Type α error

Question 14

A brokerage firm needs information concerning the standard deviation of the account balances of its customers.From previous information it was assumed to be $250. A random sample of 61 accounts was checked. Thestandard deviation was $286.20. At α = 0.01, test the firmʹs assumption. Assume that the account balances arenormally distributed.

Accepted Answer

The answer of A brokerage firm needs information concerning the...

Question 15

Determine the critical value,  ZO  to test the claim about the population proportion  p=0.250  given  n=48  and $\hat { \mathrm { p } } = 0.231 . \text { Use } \alpha = 0.01$

Accepted Answer

A) $\pm 2.575$ 
B)  $\pm 1.96$ 
C)  $\pm 1.645$ 
D)  $\pm 2.33$

Question 16

Find the standardized test statistic t for a sample with $$\mathrm { n } = 15 , \overline { \mathrm { x } } = 10.1 , \mathrm {~s} = 0.8 , \text { and } \alpha = 0.05 \text { if } \mathrm { H } _ { 0 } : \mu \leq 9.8 . \text { Round }$$ your answer to three decimal places.

Accepted Answer

A)  1.452 
B)  1.728 
C)  1.631 
D)  1.312

Question 17

If β is computed to be 0.763, then the power of the test is

Accepted Answer

A)  0.237. 
B)  0.763. 
C)  0.263. 
D)  0.737.

Question 18

The dean of a major university claims that the mean number of hours students study at her University (perday) is at most 3.6 hours. If a hypothesis test is performed, how should you interpret a decision that rejects thenull hypothesis?

Accepted Answer

A)  There is sufficient evidence to reject the claim $\mu \leq 3.6$. 
B)  There is not sufficient evidence to reject the claim $\mu \leq 3.6$. 
C)  There is sufficient evidence to support the claim $\mu \leq 3.6$. 
D)  There is not sufficient evidence to support the claim $\mu \leq 3.6$.

Question 19

The mean age of lawyers in New York is 50.7 years. Write the null and alternative hypotheses.

Accepted Answer

The answer of The mean age of lawyers in New...

Question 20

Suppose you want to test the claim that $\mu > 25.6$ Given a sample size of  n=53  and a level of significance of $\alpha = 0,01$ when should you reject  H0  ?

Accepted Answer

A)  Reject  H0  if the standardized test statistic is greater than  2.33 . 
B)  Reject  H0  if the standardized test statistic is greater than  1.96 . 
C)  Reject  H0  if the standardized test statistic is greater than  2.575 . 
D)  Reject  H0  if the standardized test statistic is greater than  1.645 .

Exam 10: Hypothesis Tests Regarding a Parameter

The mean utility bill in one city during the summer was less than $90. Write the null and alternativehypotheses.

Test the claim that Assume that the population is normally distributed.

Test the claim that Assume that the population is normally distributed.

The mean annual return for an employeeʹs IRA is at most 3.4 percent. Write the null and alternativehypotheses.

Find the standardized test statistic t for a sample with $\mathrm { n } = 10 , \overline { \mathrm { x } } = 7.9 , \mathrm {~s} = 1.3 \text {, and } \alpha = 0.05 \text { if } \mathrm { H } _ { 0 } : \mu \geq 8.8 \text {. Round }$ your answer to three decimal places.

True or False: Type I and Type II errors are independent events.

If we reject the null hypothesis when the null hypothesis is true, then we have made a

Determine the critical value, ZO to test the claim about the population proportion p=0.250 given n=48 and $\hat { \mathrm { p } } = 0.231 . \text { Use } \alpha = 0.01$

Find the standardized test statistic t for a sample with $\mathrm { n } = 15 , \overline { \mathrm { x } } = 10.1 , \mathrm {~s} = 0.8 , \text { and } \alpha = 0.05 \text { if } \mathrm { H } _ { 0 } : \mu \leq 9.8 . \text { Round }$ your answer to three decimal places.

If β is computed to be 0.763, then the power of the test is

The dean of a major university claims that the mean number of hours students study at her University (perday) is at most 3.6 hours. If a hypothesis test is performed, how should you interpret a decision that rejects thenull hypothesis?

The mean age of lawyers in New York is 50.7 years. Write the null and alternative hypotheses.

Suppose you want to test the claim that $\mu > 25.6$ Given a sample size of n=53 and a level of significance of $\alpha = 0,01$ when should you reject H₀ ?

Exam 10: Hypothesis Tests Regarding a Parameter

The mean utility bill in one city during the summer was less than $90. Write the null and alternativehypotheses.

Test the claim that Assume that the population is normally distributed.

Test the claim that Assume that the population is normally distributed.

The mean annual return for an employeeʹs IRA is at most 3.4 percent. Write the null and alternativehypotheses.

True or False: Type I and Type II errors are independent events.

If we reject the null hypothesis when the null hypothesis is true, then we have made a

Determine the critical value, ZO to test the claim about the population proportion p=0.250 given n=48 and p^=0.231. Use α=0.01\hat { \mathrm { p } } = 0.231 . \text { Use } \alpha = 0.01p^​=0.231. Use α=0.01

If β is computed to be 0.763, then the power of the test is

The dean of a major university claims that the mean number of hours students study at her University (perday) is at most 3.6 hours. If a hypothesis test is performed, how should you interpret a decision that rejects thenull hypothesis?

The mean age of lawyers in New York is 50.7 years. Write the null and alternative hypotheses.

Suppose you want to test the claim that μ>25.6\mu > 25.6μ>25.6 Given a sample size of n=53 and a level of significance of α=0,01\alpha = 0,01α=0,01 when should you reject H0 ?

Determine the critical value, ZO to test the claim about the population proportion p=0.250 given n=48 and $\hat { \mathrm { p } } = 0.231 . \text { Use } \alpha = 0.01$

Suppose you want to test the claim that $\mu > 25.6$ Given a sample size of n=53 and a level of significance of $\alpha = 0,01$ when should you reject H₀ ?