Exam 10: Testing Hypotheses About Proportions

A large software development firm recently relocated its facilities. Top management is interested in fostering good relations with their new local community and has Encouraged their professional employees to engage in local service activities. They Believe that at least 40% or more of the employees engage in these types of activities. If This is not the case, they will institute an incentive program to increase community Involvement. The correct null and alternative hypotheses to test the belief of top Management are

A company that has a 10% market share launches a marketing campaign. At the end of the campaign period, the company conducts a survey in order to assess whether its Market share has increased. The result of the survey issued to 500 customers was 12.5%. What is the associated p-value?

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? A. Write the null and alternative hypotheses. b. What is the value of the test statistic? c. What is the associated P-value? d. State your conclusion using α = 0.05.

Business decisions should always take into consideration which of the following?

A company manufacturing computer chips finds that 8% of all chips manufactured are defective. Management is concerned that high employee turnover is partially responsible For the high defect rate. 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. Was is the P-value for this proportion test?

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 value of the test statistic for Testing this claim is

Suppose minorities form 29% of a local population. A local business has 125 employees, of which 28 are minorities. Did the business discriminate in its hiring Practices?

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. What is the value of the test Statistic?

If a P-value = 0.1039 at α = 0.05

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. A. Write the null and alternative hypotheses. b. 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? Explain.

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. After the program is completed, employees are Surveyed to see if a greater percentage is now open to innovativeness and change. The Correct alternative hypothesis is

A company that has a 10% market share launches a marketing campaign. At the end of the campaign period, the company conducts a survey in order to assess whether its market share has increased. The result of the survey issued to 500 customers was 12.5%. A. Write the null and alternative hypotheses. b. What is the value of the test statistic? c. What is the associated P-value? d. State your conclusion using α = 0.05.

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. Use alpha = 0.05 A. Write the null and alternative hypotheses. b. Let's perform a one sample z-test for proportions: What is the value of the test statistic? c. What is the associated P-value?

A business school has found that over the years, out of all the students who are offered admission, the proportion who accept is 0.70. After a new director of admissions is hired, the university wants to check if the proportion of students accepting has changed significantly. Suppose they offer admission to 1200 students and 888 accept. Is this evidence of a change from the status quo? A. Write the null and alternative hypotheses. b. Let's perform a one sample z-test for proportions: What is the value of the test statistic? c. What is the associated P-value? d. State your conclusion using α = 0.05.

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 result of this test is

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. The correct value of the test statistic is

Suppose minorities form 29% of a local population. A local business has 125 employees, of which 28 are minorities. Did the business discriminate in its hiring practices? A. Write the null and alternative hypotheses. b. What is the value of the test statistic? c. What is the associated P-value? d. State your conclusion using α = 0.05.

Suppose that you are conducting a two tailed test about a proportion at the 0.01 level of significance. The correct critical value(s) to be used in drawing a conclusion is (are)

A satellite TV provider finds that 15% of their customers switch providers when a discount offer expires. A consultant tries a small experiment and offers a random sample Of customers a free 6 months of service if they commit to staying as a customer for two Years. Not surprisingly, they find that the new switching rate is lower by a statistically Significant amount. Should they offer short-term discounts to all their customers?

A company manufacturing computer chips finds that 8% of all chips manufactured are defective. Management is concerned that high employee turnover is partially responsible for the high defect rate. 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. Was the additional training effective in lowering the defect rate? A. Write the null and alternative hypotheses. b. What is the value of the test statistic? c. What is the associated P-value? d. State your conclusion using α = 0.01.