Question

A manufacturer claims that the life span of its tires is 52,000 miles. You work for a consumer protection agency and you are testing these tires. Assume the life spans of the tires are normally distributed. You select 100 tires at random and test them. The mean life span is 51.831 miles. Assume sigma = 800.

Complete parts​ (a) through​ (c).

(a) Assuming the​ manufacturer's claim is​ correct, what is the probability that the mean of the sample is

51,831 miles or​ less?

(_______) ​(Round to four decimal places as​ needed.)

​(b) Using your answer from part​ (a), what do you think of the​ manufacturer's claim?

The claim is (accurate or inaccurate) because the sample mean (would or would not) be considered unusual since it (lies or does not lie) within the range of a usual​ event, namely within (1 or 2 or 3 standard deviations) of the mean of the sample means.

​(c) Assuming the​ manufacturer's claim is​ true, would it be unusual to have an individual tire with a life span of 51,831 miles? Why or why​ not?

(Yes or No)​, because 51,831 (lies or does not lie) within the range of a usual​ event, namely within (1 or 2 or 3 standard deviations) of the mean for an individual tire.

Answer 1