A tire manufacturer claims that the life span of its tires is52,000 miles. Assume the life spans of the tire are normallydistributed. You selected 16 tires at random and tested them. Themean life span of the sample is 50,802 miles. The tires had apopulation standard deviation, σ = 800. Use the .05 level ofsignificance. a) Which distribution would be indicated? b) Explainwhy you chose that distribution. c) Construct a confidence intervalfor the mean using the above data. Use the .05 level ofsignificance. d) Re-compute the confidence interval if “n†isincreased to 125 with the same mean and standard deviation. e)Re-compute the confidence interval if level of significance .01with the same mean and standard deviation with the original n.
