Question

A random sample of vehicles (n=36) were selected and fitted with a new brake design. A standardized braking test was then performed on all the vehicles and the stopping distances were recorded. The population stopping distance using this test is a mean of μ=65 feet with a standard deviation of σ= 12 feet. You find that the mean stopping distance for your sample is 60 feet. Your job is too determine is the new brake design significantly decreased the stopping distance of these vehicles at an alpha level of .05.

What is your statistical decision and conclusion regarding the effectiveness of the new brake design, at an alpha level of .05?

A. Retain the null. The new brakes had no significant effect on stopping distance.

B. Reject the null. The new brakes had no significant effect on stopping distance.

C. Retain the null. The new brakes significantly reduced stopping distance.

D. Reject the null. The new brakes significantly reduce stopping distance.

Answer 1

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