A researcher knows from past studies that the standard deviation of the time it takes to inspect a car is 16.8 minutes. A sample of 24 cars is selected and inspected. The standard deviation was 12.5...

A researcher knows from past studies that the standard deviation of the time it takes to inspect a car is 16.8 minutes. A sample of 24 cars is selected and inspected.

The standard deviation was 12.5 minutes. At alpha 0.05, can it be concluded that the standard deviation has changed?

Find the p-value. On the basis of the p-value, should the null hypothesis be rejected at alpha 0.05?