You work for a consumer watchdog publication and are testing the advertising claims of a tire manufacturer. The manufacturer claims that the life spans of the tires are normally? distributed, with a...

You work for a consumer watchdog publication and are testing the advertising claims of a tire manufacturer. The manufacturer claims that the life spans of the tires are normally? distributed, with a mean of? 40,000 miles and a standard deviation of 7500 miles. You test 16 tires and get the following life spans. Find the mean and standard deviation of your sample.