The marketing manager for an automobile manufacturer is interested in determining the proportion of new compact-car owners who would have purchased a passengerside 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 and decided not to reject the null hypothesis, what conclusion could you draw?
a) z-test of a population mean
b) z-test of a population proportion
c) t-test of population mean
d) x2 -test of population variance