Question

a. A car manufacturer aims to improve the quality of the products by reducing the defects. The manufacturer monitors the efficiency of two assembly lines. In line A there are 18 defects reported out of 1000 cars, while in line there are 25 defects out of 1600 cars. The manufacturer wants to determine whether there are any differences between these two assembly lines. (3 points)

A. One-sample test for the population mean

B. Independent two-sample test for the difference in population means

C. Paired two-sample test for the difference in population means

D. One-sample test for the population proportion

E. Independent two-sample test for the difference in population proportions F. Paired two-sample test for the difference in population proportions

b. Recent nutrition study suggests that people who eat a high-carbonated food start to crave shortly afterwards. In a study, two groups of adults are given similar test meals, one is rich in carbohydrates and the other is not. After four hours, brains scans are used to determine if there is any activity related to craving (present or absent). The results obtained in these two groups are compared. (3 points)

A. One-sample test for the population mean

B. Independent two-sample test for the difference in population means

C. Paired two-sample test for the difference in population means

D. One-sample test for the population proportion

E. Independent two-sample test for the difference in population proportions

F. Paired two-sample test for the difference in population proportions

c. Officers of the police department are concerned about the safety of drivers along Interstate 95. They are interested in seeing how fast drivers typically go. The speed limit is 75 mph. But the officers suspect that drivers go faster. (3 points)

A. One-sample test for the population mean

B. Independent two-sample test for the difference in population means

C. Paired two-sample test for the difference in population means

D. One-sample test for the population proportion

E. Independent two-sample test for the difference in population proportions

F. Paired two-sample test for the difference in population proportions

Answer 1

a)

[E] independent two sample test for the difference in population proportions.

here two samples are given and the number of defects are given and we need to test is the proportion of defects between two assembly lines are different.

b)

[B] independent two sample test for the difference in population means.

here two different samples are given.

c)

[A] one sample test for the population mean.

here we need to test the average speed is 75mph as claim is greater than 75mph.

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