A manufacturer claims that the life span of its tires is 51,000 miles. You work
ID: 3046604 • Letter: A
Question
A manufacturer claims that the life span of its tires is 51,000 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 50,865 miles. Assume sigma =700. Complete parts (a) through (c). (a) Assuming the manufacturer's claim is correct, what is the probability that the mean of the sample is 50,865 miles or less? nothing (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 inaccurate because the sample mean would not would be considered unusual since it does not lie lies within the range of a usual event, namely within 1 standard deviation 2 standard deviations 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 50 comma 865 miles? Why or why not? No Yes , because 50 comma 865 does not lie lies within the range of a usual event, namely within 1 standard deviation 2 standard deviations 3 standard deviations of the mean for an individual tire.
Explanation / Answer
probability that the mean of the sample is 50,865 miles or less
b) The claim is accurate because the sample mean would not be considered unusual since it lies within the range of a usual event, namely within 2 standard deviations of the mean of the sample means.
c)
No because 50 comma 865 lies within the range of a usual event, namely within 2 standard deviations of the mean for an individual tire.
for normal distribution z score =(X-)/ here mean= = 51000.000 std deviation == 700.00 sample size =n= 100 std error=x=/n= 70.0000Related Questions
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