A tire company has developed a new tread design and claim that the newly designed tire...

A tire company has developed a new tread design and claim that the newly designed tire has a mean life of 60,000 miles or more.

To examine the claim, a random sample of 16 prototype tires is tested. The mean tire life for this sample is 60,758 miles.

Assume that the tire life is normally distributed with unknown mean µ and standard deviation σ=1500 miles.

(a) Please construct a 90% confidence interval for the mean life of the new designed tire.

Does your confidence interval support the company’s claim?

(b) How would you set up a hypothesis to test the claim?

Please use α=0.05. Is your conclusion consistent with part (a)?

Solutions

Expert Solution

Since lower bound of the confidence interval > 60000, so we can conclude that there is sufficient evidence to support the claim that the newly designed tire has a mean life of more than 60,000 miles.

orchestra answered 1 year ago

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