A consumer group plans to test whether a new passenger car that is advertised to have a mean highway miles per gallon of at least 33 actually meets this level. They plan to test the hypothesis using a significance level of 0.05 and a sample size of n = 100 cars. It is believed that the population standard deviation is 3 mpg. Based upon this information, if the "true" population mean is 32.0 mpg, what is the probability that the test will lead the consumer group to reject the claimed mileage for this car?
A) About 0.075
B) Approximately 0.95
C) 0.05
D) None of the above

Question

Quizplus · Accepted Answer

The probability of rejecting the null hypothesis when the true mean is 32 mpg (less than the claimed 33 mpg) is the power of the test. Using the standard normal distribution, the power is approximately 0.95.

A Consumer Group Plans to Test Whether a New Passenger