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posted by Karinna .
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 this manufacturer's 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 49,271 miles. Assume รณ = 800 miles. Assuming the manufacturer's claim is correct, what is the probability the mean of the sample is 49,271 miles or less.
 I used the central limit theorem to answer the question..I'm not sure of my answer. I just wanted to check it with somebody else's answer to make sure I did it right ...Thank you for taking time to read this.
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