A manufacture 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 these tires are normally distributed. You select 100 tires at random and test them. The mean life span is 51,775. Assume o=700.
(a) What is the probability that the mean of the sample is 51,775 miles or less?
(b) The claim is inaccurate or accurate 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 1,2, or 3 standard deviation of the mean of the sample means.
(c) Assuming the manufactors claim is true, would it be unusual to have an individual tire with a life span of 51,775 miles?
Yes or no? because 51,775 lies or does not lie within the range of a usual event, namely within 1, 2, or 4 standard deviations of the mean of an individual tire.