A research engineer for a tire manufacturer is investigating tire life for a new rubber compound and has built 16 tires and tested them to end-of-life in a road test. The sample mean and standard deviation are 60,139.7 and 3503.90 kilometers.
Can you conclude, using $\alpha = 0.05$, that the standard deviation of tire life is less than 4000 kilometers?
There sufficient evidence to indicate the true standard deviation of tire life is less than 4000 km at $\alpha = 0.05$.
State bounds for the P-value of this test.
0.1 < P-value < 0.5
0.01 < P-value < 0.05
0.7 < P-value < 0.9
0.001 < P-value < 0.005
Do we assume that the data come from a population with a normal distribution?