Question 1

A survey claims that 7 out of 10 customers recommend Western Drugs for pharmacy issues. To test this claim, a random sample of 100 customers is obtained from the list of Rewards customers. Of these 100 customers, 75 indicate that they recommend using Western Drugs for pharmacy needs. We would like to know if this claim is accurate.

Accepted Answer

A)  $H _ { 0 } : \mathrm { p } = 0.70 \text { and } H _ { A } : \mathrm { p } \neq 0.70$ 
B)  $H _ { 0 } : \mathrm { p } = 0.70 \text { and } H _ { A } : \mathrm { p } > 0.75$ 
C)  $H _ { 0 } : \mathrm { p } = 0.70 \text { and } H _ { A } : \mathrm { p } < 0.70$ 
D)  $H _ { 0 } : \mathrm { p } \neq 0.70 \text { and } H _ { A } : \mathrm { p } = 0.70$ 
E)  $H _ { 0 } : \mathrm { p } = 0.75 \text { and } H _ { A } : \mathrm { p } \neq 0.75$

Question 2

A company that sells eco-friendly cleaning products is concerned that only 19.5% of people who use such products select their brand. A marketing director suggests that the
Company invest in new advertising and labeling to strengthen its green image. The
Company decides to do so in a test market so that the effectiveness of the marketing
Campaign may be evaluated. Based on data collected in the test market, the company
Constructed a 98% confidence interval for the proportion of all consumers who might buy
Their brand. The resulting interval is 16% to 28%. What conclusion should the
Company reach about the new marketing campaign?

Accepted Answer

A)  The data do not provide convincing evidence that the marketing campaign increases
The percentage of customers for the company's products. 
B)  The data do provide convincing evidence that the marketing campaign increases the
Percentage of customers for the company's products. 
C)  The new marketing campaign is effective in increasing the percentage of customers
Buying their brand. 
D)  The company should launch the new marketing campaign. 
E)  None of the above.

Question 3

A survey claims that 7 out of 10 customers recommend Western Drugs for pharmacy issues. To test this claim, a random sample of 100 customers is obtained from the list of
Rewards customers. Of these 100 customers, 75 indicate that they recommend using
Western Drugs for pharmacy needs. We would like to know if this claim is accurate.
State your conclusion using α = 0.05.

Accepted Answer

A)  The null hypothesis is not supported: more than 70% of customers recommend
Western Drugs for pharmacy issues. 
B)  The null hypothesis is not supported: less than 70% of customers recommend Western
Drugs for pharmacy issues. 
C)  The null hypothesis is not supported: the percentage of customers who recommend
Western Drugs for pharmacy issues is not equal to 75%. 
D)  More information is required to draw a valid conclusion 
E)  The null hypothesis is supported: 70% of customers recommend Western Drugs for
Pharmacy issues.

Question 4

A report on the U.S. economy indicates that 28% of Americans have experienced difficulty in making mortgage payments. A news organization randomly sampled 400 Americans from 10 cities named the "fastest dying cities in the U.S." (Forbes Magazine, August 2008) and found that 136 reported such difficulty. Does this indicate that the Problem is more severe among these cities? The correct null and alternative hypotheses For testing this claim are

Accepted Answer

A)  $H _ { 0 } : p = 0.28 \text { and } H _ { A } : p > 0.28$ 
B)  $H _ { 0 } : p = 0.28 \text { and } H _ { A } : p  0.28 \text { and } H _ { A } : p = 0.28$

Question 5

A national study report released by the Center for Studying Health System Change (HSC) in 2010, indicated that 20.9% of Americans were identified as having medical bill
Financial issues. Many people in families with problems paying medical bills in 2010
Experienced severe financial consequences from their medical debt, with about two-thirds
Reporting problems paying for other necessities and a quarter considering bankruptcy, the
Study found. What if a news organization randomly sampled 400 Americans from 10
Cities and found that 90 reported having such difficulty. A test was done to investigate
Whether the problem is more severe among these cities. The p-value for this test is

Accepted Answer

A)  0.2156 
B)  0.0539 
C)  0.1078 
D)  0.4312 
E)  None of the above.

Question 6

Top management of a large multinational corporation wants to create a culture of innovativeness and change. A consultant hired to assess the company's organizational Culture finds that only 15% of employees are open to new ideas and approaches toward Their work. Consequently the company conducts a program for employees in order to Reinforce the new corporate philosophy. Based on data collected after the program, the Finds the 95% confidence interval for the proportion of all employees open to new ideas To be 18% to 22%. What should the company conclude?

Accepted Answer

A)  The null hypothesis should not be rejected. 
B)  There is no evidence to suggest that the program improved employees' attitudes Toward innovativeness and change. 
C)  There is evidence that the program improved employees' attitudes toward Innovativeness and change. 
D)  Both A and B. 
E)  Both A and C.

Question 7

A company manufacturing computer chips finds that 8% of all chips manufactured are defective. In an effort to decrease the percentage of defective chips, management decides
To provide additional training to those employees hired within the last year. After
Training was implemented, a sample of 450 chips revealed only 27 defects. A hypothesis
Test is performed to determine if the additional training was effective in lowering the
Defect rate. Which of the following statement is true about this hypothesis test?

Accepted Answer

A)  It is a two tailed test about a proportion. 
B)  It is a one tailed test about a mean. 
C)  It is a one tailed test about a proportion. 
D)  It is a two tailed test about a mean. 
E)  None of the above.

Exam 10: Testing Hypotheses About Proportions