QA Chapter 14 (Test 3)

3. Vending machines on a college campus offer a variety of snacks. The purchasing agent believes that each type of snack is equally preferred by students and consequently orders equal quantities. The number of snacks sold from vending machines on this campus for the last six months is shown in the following table. If the purchasing agent is correct, how many candy bars would we expect to have been sold? A. 170 B. 198 C. 125 D. 180 E. 680

A. 170

8. A manufacturing plant for recreational vehicles receives shipments from three different parts vendors. There has been a defect issue with some of the electrical wiring in the recreational vehicles manufactured at the plant. The plant manager believes that the defect issue is dependent on the parts vendor. The plant manager reviews a sample of quality assurance inspections from the last six months. The expected number of perfect parts from Made-4-U Co. is A. 75.9 B. 91.08 C. 71 D. 61.81 E. 252

A. 75.9

10. A real estate agency, located in a metropolitan area in the northeastern U.S., kept data on the various types of properties purchased in the area. Historically, 15% of purchases were for condominiums, 30% were for townhouses, 40% for single family homes, 10% for commercial properties and 5% for land. Based on the data shown below, the null hypothesis was rejected and the agency concluded that the current distribution of property sales differs from the historical distribution. Based on an examination of the standardized residuals, which type of property had the most impact on the test results? A. Condos B. Townhouses C. Homes D. Commercial E. Land

A. Condos

15T. Chris Columbus is responsible for controlling inventory levels for four types of sailboats sold by his company. Chris takes a sample of 48 boats sold over the past several months to determine if demand is the same for each type. His results are as follows: At the 0.05 level of significance, the correct conclusion is A. Evidence suggests that the demand is the same for different types of boats. B. Evidence suggests that the demand is not the same for different types of boats. C. Reject the null hypothesis. D. Both A and C. E. Both B and C.

A. Evidence suggests that the demand is the same for different types of boats.

6. A real estate agency, located in a metropolitan area in the northeastern U.S., kept data on the various types of properties purchased in the area. Historically, 15% of purchases were for condominiums, 30% were for townhouses, 40% for single family homes, 10% for commercial properties and 5% for land. With changing demographics, the agency wondered if the current distribution matches the historical distribution. Recent data showed the following: Which Chi-square test is most appropriate for this situation? A. Goodness of Fit B. Homogeneity C. Independence D. Proportional E. None of the above.

A. Goodness of Fit

5. Before being released to market, a drug company tests a new allergy medication for potential side effects. A random sample of 160 individuals with allergies was selected for the study. The new allergy medication was randomly assigned to 80 of them, and another popular allergy medication already on the market (Brand C) was assigned to the rest. Out of the 80 given the new allergy medication, 14 reported drowsiness; 22 of the 80 taking Brand C reported drowsiness. The 95% confidence interval for the difference in proportions reporting drowsiness is -0.028 to 0.228. Which of the following is correct? A. We are 95% confident that there is no difference between the proportions of patients reporting drowsiness for the two allergy medications. B. We are 95% confident that there is a difference between the proportions of patients reporting drowsiness for the two allergy medications. C. We are 95% confident that the proportion of patients reporting drowsiness is higher for the new allergy medication. D. We are 95% confident that the proportion of patients reporting drowsiness is lower for the new allergy medication. E. There will be a significant difference between the proportions 95% of the time.

A. We are 95% confident that there is no difference between the proportions of patients reporting drowsiness for the two allergy medications.

2. An online department store wants to determine if there is an association between coupon redemption and gender. After a special coupon broadcast to its reward members, the following data on coupon redemption at check out were collected. The correct value of the test statistic is A. χ 2 = 5.339 B. χ 2 = 8.429 C. χ 2 = 0.839 D. χ 2 = 45.556 E. None of the above.

A. χ 2 = 5.339

4. Vending machines on a college campus offer a variety of snacks. The purchasing agent believes that each type of snack is equally preferred by students and consequently orders equal quantities. The number of snacks sold from vending machines on this campus for the last six months is shown in the following table. The correct value of the test statistic for determining if the purchasing agent's belief if supported is A. χ 2 = 8.012 B. χ 2 = 12.019 C. χ 2 = 0.984 D. χ 2 = 45.014 E. None of the above.

A. χ 2 = 8.012

4. Previous surveys reported that more men than women trade stocks online. A local brokerage firm randomly selected a sample of investors. They found that 45 out of 234 men traded online and 42 out of 251 women traded online. The 95% confidence interval for the difference in proportions is A. 4% to 9% B. -4% to 9% C. 2% to 12% D. -2% to 12% E. -2% to -4%

B. -4% to 9%

14T. Chris Columbus is responsible for controlling inventory levels for four types of sailboats sold by his company. Chris takes a sample of 48 boats sold over the past several months to determine if demand is the same for each type. His results are as follows: The calculated value of the Chi Square statistic is A. 7.815 B. 1.17 C. 22.35 D. -1.17 E. 12.56

B. 1.17

6. A manufacturing plant for recreational vehicles receives shipments from three different parts vendors. There has been a defect issue with some of the electrical wiring in the recreational vehicles manufactured at the plant. The plant manager believes that the defect issue is dependent on the parts vendor. The plant manager reviews a sample of quality assurance inspections from the last six months. Which Chi-square test is most appropriate for this situation? A. Goodness of Fit B. Homogeneity C. Dependence D. Proportional E. None of the above.

B. Homogeneity

2. Vending machines on a college campus offer a variety of snacks. The purchasing agent believes that each type of snack is equally preferred by students and consequently orders equal quantities. The null hypothesis to test his belief can be worded as A. The types of snacks are not uniformly distributed among the students buying snacks. B. The types of snacks are uniformly distributed among the students buying snacks. C. The types of snacks are independent from each other. D. The distribution of type of snack purchases follows the normal distribution. E. None of the above.

B. The types of snacks are uniformly distributed among the students buying snacks.

8. A real estate agency, located in a metropolitan area in the northeastern U.S., kept data on the various types of properties purchased in the area. Historically, 15% of purchases were for condominiums, 30% were for townhouses, 40% for single family homes, 10% for commercial properties and 5% for land. With changing demographics, the agency wondered if the current distribution matches the historical distribution. Recent data showed the following: The value of the Chi-square test statistic is A. χ 2 = 5.993 B. χ 2 = 62.538 C. χ 2 = 101.482 D. χ 2 = 77.431 E. χ 2 = 8.101

B. χ 2 = 62.538

7. A real estate agency, located in a metropolitan area in the northeastern U.S., kept data on the various types of properties purchased in the area. Historically, 15% of purchases were for condominiums, 30% were for townhouses, 40% for single family homes, 10% for commercial properties and 5% for land. With changing demographics, the agency wondered if the current distribution matches the historical distribution. Recent data showed the following: Based on the historical distribution, we would expect how many homes to be purchased? A. 121 B. 122.54 C. 130 D. 129.95 E. 100

C. 130

7. A manufacturing plant for recreational vehicles receives shipments from three different parts vendors. There has been a defect issue with some of the electrical wiring in the recreational vehicles manufactured at the plant. The plant manager believes that the defect issue is dependent on the parts vendor. The plant manager reviews a sample of quality assurance inspections from the last six months. The expected number of rejected parts from Perfect Parts Co. is A. 53 B. 51.51 C. 57.68 D. 61.81 E. 171

C. 57.68

1. Vending machines on a college campus offer a variety of snacks. The purchasing agent believes that each type of snack is equally preferred by students and consequently orders equal quantities. The number of snacks sold from vending machines on this campus for the last six months is shown in the following table. The appropriate test to see if the purchasing agent is correct is the A. Chi-square test of independence. B. Z-test for two proportions. C. Chi-square goodness-of-fit test. D. Chi-square test of homogeneity. E. Normality test.

C. Chi-square goodness-of-fit test.

1. An online department store wants to determine if there is an association between coupon redemption and gender. After a special coupon broadcast to its reward members, the following data on coupon redemption at check out were collected. Which Chi-square test is most appropriate for this situation? A. Goodness of Fit B. Homogeneity C. Independence D. Proportional E. None of the above.

C. Independence

13T. Chris Columbus is responsible for controlling inventory levels for four types of sailboats sold by his company. Chris takes a sample of 48 boats sold over the past several months to determine if demand is the same for each type. His results are as follows: The correct null hypothesis to be tested is A. Type of boat and demand are related. B. The demand differs for each type of boat. C. The demand is the same for each type of boat. D. Both A and B. E. Both A and C.

C. The demand is the same for each type of boat.

9. A real estate agency, located in a metropolitan area in the northeastern U.S., kept data on the various types of properties purchased in the area. Historically, 15% of purchases were for condominiums, 30% were for townhouses, 40% for single family homes, 10% for commercial properties and 5% for land. With changing demographics, the agency wondered if the current distribution matches the historical distribution. Recent data showed the following: What is the standardized residual associated with Townhouses? A. 23.5 B. 4.85 C. 10.86 D. 2.38 E. Not enough information given to calculate.

D. 2.38

3. An online department store wants to determine if there is an association between coupon redemption and gender. After a special coupon broadcast to its reward members, the following data on coupon redemption at check out were collected. The P-value associated with the calculated Chi-square statistic is 0.0209. At α = 0.05 the correct conclusion is A. to reject the null hypothesis. B. to accept the null hypothesis. C. to conclude that there is an association between coupon redemption and gender. D. Both A and C. E. Both B and C.

D. Both A and C.

5. Vending machines on a college campus offer a variety of drinks. The purchasing agent believes that each type of snack is equally preferred by students and consequently orders equal quantities. The number of snacks sold from vending machines on this campus for the last six months is shown in the following table. The P-value of the calculated Chisquare statistic is 0.0458. At α = 0.05, we should A. reject the null hypothesis. B. not reject the null hypothesis. C. conclude that the purchasing agent was not correct. D. Both A and C. E. Both B and C.

D. Both A and C.

9. A manufacturing plant for recreational vehicles receives shipments from three different parts vendors. There has been a defect issue with some of the electrical wiring in the recreational vehicles manufactured at the plant. The plant manager believes that the defect issue is dependent on the parts vendor. The plant manager reviews a sample of quality assurance inspections from the last six months. The correct value of the test statistic for determining if the plant manager's belief is supported is A. χ 2 = 8.10 B. χ 2 = 6.52 C. χ 2 = 5.03 D. χ 2 = 7.40 E. χ 2 = 9.89

D. χ 2 = 7.40

20T. The residual, or the difference, between the observed frequency and the expected frequency is a reliable indicator. A standardized residual can also be computed for each cell. Which statements are true about standardized residuals? A. Standardized residuals that have a positive value mean that the cell was overrepresented in the actual sample, compared to the expected frequency. B. The standardized residual can be compared against the critical z-value for your α level to determine significance. C. Standardized residuals can be used to test the null hypothesis that the actual frequency equals the expected frequency for a specific cell versus the research hypothesis of a difference greater than zero. D. Standardized residuals that have a negative value mean that the cell was underrepresented in the actual sample, compared to the expected frequency. E. All of the above.

E. All of the above.

10. A manufacturing plant for recreational vehicles receives shipments from three different parts vendors. There has been a defect issue with some of the electrical wiring in the recreational vehicles manufactured at the plant. The plant manager believes that the defect issue is dependent on the parts vendor. The plant manager reviews a sample of quality assurance inspections from the last six months. The P-value of the calculated Chisquare statistic is 0.1161. At α = 0.05, we should A. reject the null hypothesis. B. not reject the null hypothesis. C. conclude that the defects do not vary by vendor. D. both A and C. E. both B and C.

E. both B and C.