Question 1

SCENARIO 9-4
A drug company is considering marketing a new local anesthetic.The effective time of the anesthetic the drug company is currently producing has a normal distribution with a mean of
7.4 minutes with a standard deviation of 1.2 minutes.The chemistry of the new anesthetic is such that the effective time should be normally distributed with the same standard deviation, but the mean effective time may be lower.If it is lower, the drug company will market the new anesthetic; otherwise, they will continue to produce the older one.A sample of size 36 results in a sample mean of 7.1.A hypothesis test will be done to help make the decision.
-Referring to Scenario 9-4, if the level of significance had been chosen as0.05, the company would market the new anesthetic.

Accepted Answer

A) True 
 B)False

Question 2

The owner of a local nightclub has recently surveyed a random sample of n = 250 customers of the club.She would now like to determine whether or not the mean age of her customers is greater than 30.If so, she plans to alter the entertainment to appeal to an older crowd.If not, no entertainment changes will be made.The appropriate hypotheses to test are: a) $H _ { 0 } : \mu \geq 30$ versus $H _ { 1 } : \mu < 30$ b) $H _ { 0 } : \mu \leq 30$ versus $H _ { 1 } : \mu > 30$. c) $H _ { 0 } : \bar { X } \geq 30$ versus $H _ { 1 } : \bar { X } < 30$. d) $H _ { 0 } : \bar { X } \leq 30$ versus $H _ { 1 } : \bar { X } > 30$.

Accepted Answer

The answer of The owner of a local nightclub has...

Question 3

For a given level of significance, if the sample size is increased but the summary statistics remain the same, the probability of committing a Type II error will increase.

Accepted Answer

A) True 
 B)False

Question 4

A survey claims that 9 out of 10 doctors recommend aspirin for their patients with headaches.To test this claim against the alternative that the actual proportion of doctors who recommend aspirin is less than 0.90, a random sample of 100 doctors results in 83 who indicate that they recommend aspirin.The value of the test statistic in this problem is approximately equal to:

Accepted Answer

A) - 4.12 
B) - 2.33 
C) - 1.86 
D) - 0.07

Question 5

A manager of the credit department for an oil company would like to determine whether the mean monthly balance of credit card holders is equal to $75.An auditor selects a random sample of 100 accounts and finds that the mean owed is $83.40 with a sample standard deviation of $23.65.If you wanted to test whether the mean balance is different from $75 and decided to reject the null hypothesis, what conclusion could you reach?

Accepted Answer

A) There is not evidence that the mean balance is $75. 
B) There is not evidence that the mean balance is not $75. 
C) There is evidence that the mean balance is $75. 
D) There is evidence that the mean balance is not $75.

Question 6

"What conclusions and interpretations can you reach from the results of the hypothesis test?" is not an important question to ask when performing a hypothesis test.

Accepted Answer

A) True 
 B)False

Question 7

SCENARIO 9-3
An appliance manufacturer claims to have developed a compact microwave oven that consumes a mean of no more than 250 W.From previous studies, it is believed that power consumption for microwave ovens is normally distributed with a population standard deviation of 15 W.A consumer group has decided to try to discover if the claim appears true.They take a sample of 20 microwave ovens and find that they consume a mean of 257.3 W.
-Referring to Scenario 9-3, the p-value of the test is .

Accepted Answer

The answer of SCENARIO 9-3
An appliance manufacturer claims to have...

Question 8

SCENARIO 9-1
Microsoft Excel was used on a set of data involving the number of defective items found in a random sample of 46 cases of light bulbs produced during a morning shift at a plant.A manager wants to know if the mean number of defective bulbs per case is greater than 20 during the morning shift.She will make her decision using a test with a level of significance of 0.10.The following information was extracted from the Microsoft Excel output for the sample of 46 cases: $n = 46 ;$ Arithmetic Mean $= 28.00 ;$ Standard Deviation $= 25.92 ;$ Standard Error $= 3.82 ;$
Null Hypothesis: $H _ { 0 } : \mu \leq 20 ; \alpha = 0.10 ; \mathrm { df } = 45 ; T$ Test Statistic $= 2.09$;
One-Tail Test Upper Critical Value $= 1.3006 ; p$-value $= 0.021 ;$ Decision $=$ Reject.
-Referring to Scenario 9-1, the parameter the manager is interested in is:

Accepted Answer

A) the mean number of defective light bulbs per case produced at the plant. 
B) the mean number of defective light bulbs per case among the 46 cases. 
C) the mean number of defective light bulbs per case produced during the morning shift. 
D) the proportion of cases with defective light bulbs produced at the plant.

Question 9

SCENARIO 9-4
A drug company is considering marketing a new local anesthetic.The effective time of the anesthetic the drug company is currently producing has a normal distribution with a mean of
7.4 minutes with a standard deviation of 1.2 minutes.The chemistry of the new anesthetic is such that the effective time should be normally distributed with the same standard deviation, but the mean effective time may be lower.If it is lower, the drug company will market the new anesthetic; otherwise, they will continue to produce the older one.A sample of size 36 results in a sample mean of 7.1.A hypothesis test will be done to help make the decision.
-Referring to Scenario 9-4, if the level of significance had been chosen as0.05, the null hypothesis would be rejected.

Accepted Answer

A) True 
 B)False

Question 10

SCENARIO 9-10
A manufacturer produces light bulbs that have a mean life of at least 500 hours when the production process is working properly.Based on past experience, the population standard deviation is 50 hours and the light bulb life is normally distributed.The operations manager stops the production process if there is evidence that the population mean light bulb life is below 500 hours.
-Referring to Scenario 9-10, if you select a sample of 100 light bulbs and are willing to have a level of significance of 0.05, the probability of the operations manager incorrectly stopping the process when the process is in fact working properly is .

Accepted Answer

The answer of SCENARIO 9-10
A manufacturer produces light bulbs that...

Question 11

SCENARIO 9-9
The president of a university claimed that the entering class this year appeared to be larger than the entering class from previous years, but their mean SAT score is lower than previous years.He took a sample of 20 of this year's entering students and found that their mean SAT score is 1,501 with a standard deviation of 53.The university's record indicates that the mean SAT score for entering students from previous years is 1,520.He wants to find out if his claim is supported by the evidence at a 5% level of significance.
-Referring to Scenario 9-9, which of the following best describes the Type I error?

Accepted Answer

A) The president concludes that the mean SAT score of the entering students is lower than previous years when it is indeed not lower. 
B) The president concludes that the mean SAT score of the entering students is higher than previous years when it is indeed not higher. 
C) The president concludes that the mean SAT score of the entering students is not lower than previous years when it is indeed lower. 
D) The president concludes that the mean SAT score of the entering students is not higher than previous years when it is indeed higher.

Question 12

SCENARIO 9-9
The president of a university claimed that the entering class this year appeared to be larger than the entering class from previous years, but their mean SAT score is lower than previous years.He took a sample of 20 of this year's entering students and found that their mean SAT score is 1,501 with a standard deviation of 53.The university's record indicates that the mean SAT score for entering students from previous years is 1,520.He wants to find out if his claim is supported by the evidence at a 5% level of significance.
-Referring to Scenario 9-9, the null hypothesis would be rejected if a 10%probability of committing a Type I error is allowed.

Accepted Answer

A) True 
 B)False

Question 13

SCENARIO 9-2
A student claims that he can correctly identify whether a person is a business major or an agriculture major by the way the person dresses.Suppose in actuality that if someone is a business major, he can correctly identify that person as a business major 87% of the time.When a person is an agriculture major, the student will incorrectly identify that person as a business major 16% of the time.Presented with one person and asked to identify the major of this person (who is either a business or an agriculture major), he considers this to be a hypothesis test with the null hypothesis being that the person is a business major and the alternative that the person is an agriculture major.
-Referring to Scenario 9-2, what is the "actual level of significance" of the test?

Accepted Answer

A) 0.13 
B) 0.16 
C) 0.84 
D) 0.87

Question 14

For a given level of significance ( $\alpha$), if the sample size n is increased, the probability of a Type II error ( $\beta$ )

Accepted Answer

A) will decrease. 
B) will increase. 
C) will remain the same. 
D) cannot be determined.

Question 15

A pizza chain is considering opening a new store in an area that currently does not have any such stores.The chain will open if there is evidence that more than 5,000 of the20,000 households in the area have a favorable view of its brain.It conducts a telephone poll of 300 randomly selected households in the area and finds that 96 have a favorable view.The p-value associated with the test statistic in this problem is approximately equal to:

Accepted Answer

A) 0.0100 
B) 0.0051 
C) 0.0026 
D) 0.0013

Question 16

The owner of a local nightclub has recently surveyed a random sample of n = 250 customers of the club.She would now like to determine whether or not the mean age of her customers is greater than 30.If so, she plans to alter the entertainment to appeal to an older crowd.If not, no entertainment changes will be made.Suppose she found that the sample mean was 30.45 years and the sample standard deviation was 5 years.If shewants to have a level of significance at 0.01 what conclusion can she make?

Accepted Answer

A) There is not sufficient evidence that the mean age of her customers is greater than 30. 
B) There is sufficient evidence that the mean age of her customers is greater than 30. 
C) There is not sufficient evidence that the mean age of her customers is not greater than 30. 
D) There is sufficient evidence that the mean age of her customers is not greater than 30.

Question 17

SCENARIO 9-6
The quality control engineer for a furniture manufacturer is interested in the mean amount of force necessary to produce cracks in stressed oak furniture.She performs a two-tail test of the null hypothesis that the mean for the stressed oak furniture is 650 pounds.The calculated value of the Z test statistic is a positive number that leads to a p-value of 0.080 for the test.
-Referring to Scenario 9-6, suppose the engineer had decided that the alternative hypothesis to test was that the mean was less than 650.What would be the p-value of this one-tail test?

Accepted Answer

A) 0.040 
B) 0.160 
C) 0.840 
D) 0.960

Question 18

A sample is used to obtain a 95% confidence interval for the mean of a population.The confidence interval goes from 15 to 19.If the same sample had been used to test the null hypothesis that the mean of the population is equal to 20 versus thealternative hypothesis that the mean of the population differs from 20, the null hypothesis could be rejected at a level of significance of 0.02.

Accepted Answer

A) True 
 B)False

Question 19

The statement of the null hypothesis always contains an equality.

Accepted Answer

A) True 
 B)False

Question 20

The value that separates a rejection region from a non-rejection region is called the.

Accepted Answer

The answer of The value that separates a rejection region...

Exam 9: Fundamentals of Hypothesis Testing: One-Sample Tests

For a given level of significance, if the sample size is increased but the summary statistics remain the same, the probability of committing a Type II error will increase.

"What conclusions and interpretations can you reach from the results of the hypothesis test?" is not an important question to ask when performing a hypothesis test.

For a given level of significance ( $\alpha$ ) , if the sample size n is increased, the probability of a Type II error ( $\beta$ )

The statement of the null hypothesis always contains an equality.

The value that separates a rejection region from a non-rejection region is called the.

Exam 9: Fundamentals of Hypothesis Testing: One-Sample Tests

For a given level of significance, if the sample size is increased but the summary statistics remain the same, the probability of committing a Type II error will increase.

"What conclusions and interpretations can you reach from the results of the hypothesis test?" is not an important question to ask when performing a hypothesis test.

For a given level of significance ( α\alphaα ) , if the sample size n is increased, the probability of a Type II error ( β\betaβ )

The statement of the null hypothesis always contains an equality.

The value that separates a rejection region from a non-rejection region is called the.

For a given level of significance ( $\alpha$ ) , if the sample size n is increased, the probability of a Type II error ( $\beta$ )