The marketing manager for a car manufacturer is interested in determining the proportion of new compact-car owners who would have purchased a passenger-side inflatable air bag if it had been available for an additional cost of $300.The manager believes from previous information that the proportion is 0.30.Suppose that a survey of 200 new compact-car owners is selected and 79 indicate that they would have purchased the inflatable air bags.
-If you were to conduct a test to determine whether there is evidence that the proportion is different from 0.30,which test would you use?
A) Z test of a population mean.
B) t test of a population proportion.
C) Z test of a population proportion.
D) t test of a population mean.

Question

Quizplus · Accepted Answer

We need to use a test for a population proportion because we want to determine if the proportion of new compact-car owners who would have purchased the inflatable air bags is different from 0.30. Since the sample size is greater than 30 (n = 200), we can use the normal distribution and perform a z-test for a population proportion. Therefore, the correct choice is option C, the Z test of a population proportion.

The Marketing Manager for a Car Manufacturer Is Interested in Determining