Question 1

Accepted Answer

Question 2

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, state the null hypothesis for this study.

Accepted Answer

The answer of SCENARIO 9-9
The president of a university claimed...

Question 3

Which of the following would be an appropriate null hypothesis?

Accepted Answer

A)  The mean of a population is equal to 55. 
B)  The mean of a sample is equal to 55. 
C)  The mean of a population is greater than 55. 
D)  Only (a) and (c) are appropriate.

Question 4

If a researcher rejects a true null hypothesis, she has made a _______error.

Accepted Answer

The answer of If a researcher rejects a true null...

Question 5

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.
-True or False: Referring to Scenario 9-3, the null hypothesis will be rejected at 1% level of
significance.

Accepted Answer

A) True 
 B)False

Question 6

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 she wants 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 7

If a researcher does not reject a true null hypothesis, she has made a _______decision.

Accepted Answer

The answer of If a researcher does not reject a...

Question 8

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 an 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, the appropriate hypotheses are:

Accepted Answer

Question 9

Accepted Answer

Question 10

If a researcher does not reject a false null hypothesis, she has made a _______error.

Accepted Answer

The answer of If a researcher does not reject a...

Question 11

Accepted Answer

Question 12

Accepted Answer

Question 13

True or False: 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 the alternative hypothesis that the
mean of the population differs from 20, the null hypothesis could be rejected at a level of
significance of 0.05.

Accepted Answer

A) True 
 B)False

Question 14

Accepted Answer

Question 15

True or False: "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 16

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: 
-True or False: Referring to Scenario 9-1, the manager can conclude that there is sufficient
evidence to show that the mean number of defective bulbs per case is greater than 20 during the
morning shift with no more than a 5% probability of incorrectly rejecting the true null hypothesis.

Accepted Answer

A) True 
 B)False

Question 17

Accepted Answer

Question 18

Accepted Answer

Question 19

SCENARIO 9-5
A bank tests the null hypothesis that the mean age of the bank's mortgage holders is less than or equal
to 45 years, versus an alternative that the mean age is greater than 45 years.They take a sample and
calculate a p-value of 0.0202.
-True or False: Referring to Scenario 9-5, the bank can conclude that the mean age is greater
than 45 at a significance level of

Accepted Answer

A) True 
 B)False

Question 20

True or False: In testing a hypothesis, you should always raise the question concerning the
purpose of the study, survey or experiment.

Accepted Answer

A) True 
 B)False

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

Which of the following would be an appropriate null hypothesis?

If a researcher rejects a true null hypothesis, she has made a _______error.

If a researcher does not reject a true null hypothesis, she has made a _______decision.

If a researcher does not reject a false null hypothesis, she has made a _______error.

True or False: "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.

True or False: In testing a hypothesis, you should always raise the question concerning the purpose of the study, survey or experiment.