Question

A company claims that the average lifespan of a bicycle tire that they manufacture is 1200 miles. You randomly and independently collect a sample of 31 of these tires and find that the average distance these tires lasted was 1125.7 miles, with a standard deviation of 275 miles. You suspect the company is overstating how long their tires last. You formulate your suspicion as a left tailed hypothesis test. Your null hypothesis is "the average lifespan of these tires is 1200 miles."

You use an alpha of 0.05 (unless otherwise stated below) and find a p-value of 0.071.

Select all true statements.

Group of answer choices

You reject the null hypothesis.

You fail to reject the null hypothesis.

This test shows that the average lifespan of these tires is less than 1200 miles.

You may have made a Type I error with your conclusion.

You may have made a Type II error with your conclusion.

If you instead used an alpha of 0.10 you would reject the null hypothesis.

Answer 1

The solution to this problem is given by