Exam 12: Testing Hypotheses About Proportions

Consider the following to answer the question(s) below: 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? -Which of the following statement is true about this hypothesis test?

Consider the following to answer the question(s) below: Winnipeg Pet Plus believes that it has a market share of 25 percent of the local dog food market. It surveys 100 dog owners and ask whether or not it is their regular source of dog food, and 23 people say yes. -At α = 0.05

Consider the following to answer the question(s) below: 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. One of his recommendations is for the company to conduct seminars for employees in order to disseminate and reinforce the new corporate philosophy. This is done for a six month trial period after which its value in changing employee attitudes will be assessed. -Based on data collected after the trial period, the company constructed a 95% confidence interval for the proportion of all employees open to new ideas and approaches toward their work. The resulting interval is 18% to 22%. What conclusion should the company reach about the seminars? Explain.

Consider the following to answer the question(s) below: Suppose that a report indicates that 28% of Canadians have experienced difficulty in making mortgage payments. Further suppose that a news organization randomly sampled 400 Canadians from 10 cities and found that 136 reported such difficulty. Does this indicate that the problem is more severe among these cities? -State your conclusion using α = 0.05.

Consider the following to answer the question(s) below: 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. One of his recommendations is for the company to conduct seminars for employees in order to disseminate and reinforce the new corporate philosophy. This is done for a six month trial period after which its value in changing employee attitudes will be assessed. -Write the null and alternative hypotheses.

Consider the following to answer the question(s) below: 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. One of his recommendations is for the company to conduct seminars for employees in order to disseminate and reinforce the new corporate philosophy. This is done for a six month trial period after which its value in changing employee attitudes will be assessed. -In this context, describe the Type I error possible. How might such an error impact the company?

Consider the following to answer the question(s) below: Suppose that a report indicates that 28% of Canadians have experienced difficulty in making mortgage payments. Further suppose that a news organization randomly sampled 400 Canadians from 10 cities and found that 136 reported such difficulty. Does this indicate that the problem is more severe among these cities? -What is the associated P-value?

Consider the following to answer the question(s) below: Winnipeg Pet Plus believes that it has a market share of 25 percent of the local dog food market. It surveys 100 dog owners and ask whether or not it is their regular source of dog food, and 23 people say yes. -The correct value of the test statistic is

Consider the following to answer the question(s) below: Suppose that a report indicates that 28% of Canadians have experienced difficulty in making mortgage payments. Further suppose that a news organization randomly sampled 400 Canadians from 10 cities and found that 136 reported such difficulty. Does this indicate that the problem is more severe among these cities? -The P-value associated with the test statistic is

Consider the following to answer the question(s) below: 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? -The P-value associated with the test statistic is

Consider the following to answer the question(s) below: An advertising agency has developed a new ad for one of the national car manufacturing companies. The agency is interested in testing whether the proportion of favourable responses to the ad is the same between male versus female adults. It plans on conducting the test using an alpha level equal to 0.05. A sample of 100 adults of each gender will be used in the study. Each person will be asked to view the ad and indicate whether they find the ad to be "pleasing" or not. The samples resulted in 57 males and 47 females that liked the ad. -The appropriate null and alternate hypotheses are

Consider the following to answer the question(s) below: Winnipeg Pet Plus believes that it has a market share of 25 percent of the local dog food market. It surveys 100 dog owners and ask whether or not it is their regular source of dog food, and 23 people say yes. -The appropriate null and alternative hypotheses are

Consider the following to answer the question(s) below: After completing sales training for a large company, it is expected that a salesperson will generate a sale on at least 15 percent of the calls he or she makes. To make sure that the sales training process is working, a random sample of 400 sales calls made by sales representatives who have completed the training have been selected and the null hypothesis is to be tested at 0.05 alpha level. Suppose that a sale is made on 76 of the calls. -At α = 0.05

Consider the following to answer the question(s) below: 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 but 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?

Consider the following to answer the question(s) below: 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? -At α = 0.01

Consider the following to answer the question(s) below: Winnipeg Pet Plus believes that it has a market share of 25 percent of the local dog food market. It surveys 100 dog owners and ask whether or not it is their regular source of dog food, and 23 people say yes. -In this context, committing a Type I error

Consider the following to answer the question(s) below: 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 but in a test market so that the effectiveness of the marketing campaign may be evaluated. -In this context, describe the Type I error possible. How might such an error impact the company?

Consider the following to answer the question(s) below: Winnipeg Pet Plus believes that it has a market share of 25 percent of the local dog food market. It surveys 100 dog owners and ask whether or not it is their regular source of dog food, and 23 people say yes. -The P-value associated with the test statistic is

Consider the following to answer the question(s) below: Suppose that a report indicates that 28% of Canadians have experienced difficulty in making mortgage payments. Further suppose that a news organization randomly sampled 400 Canadians from 10 cities and found that 136 reported such difficulty. Does this indicate that the problem is more severe among these cities? -Write the null and alternative hypotheses.

Consider the following to answer the question(s) below: Suppose that a report indicates that 28% of Canadians have experienced difficulty in making mortgage payments. Further suppose that a news organization randomly sampled 400 Canadians from 10 cities and found that 136 reported such difficulty. Does this indicate that the problem is more severe among these cities? -At α = 0.05