A manufacturer claims that the life span of its tires is 50,000 miles. You work

Question

A manufacturer claims that the life span of its tires is 50,000 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 49,877 miles. Assume = 700 Complete parts a) through (a) Assuming the manufacturer's claim is correct, what is the probability that the mean of the sample is 49,877 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 isbecause the sample mean be considered unusual since be considered unusual since it within the range of a usual event, namely within V of the mean of the sample means. (c) Assuming the manufacturers claim is true, would it be unusual to have an individual tire with a life span of 49,877 miles? Why or why not? V, because 49,877 Vwithin the range of a usual event, namely within of the mean for an individual tire. Enter your answer in the answer hox

Explanation / Answer

a)as z score =(X-mean)*sqrt(n)/std deviation

P(Xbar<49877)=P(Z<(49877-50000)*sqrt(100)/700)=P(Z<-1.76)=0.0392 ( please try 0.0394 if this comes wrong)

b)

the claim is incorrect ; becuase the sample mean is to be considered unsuual since it does not fall within the range of a usual event; namely within 2 std deviation of the mean f the sample meams

c)

No ; because 49877 falls within the range of a usual event namely within 2 std deviation of the mean for an individual tire,.

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