A car dealer recommends that transmissions be serviced at 30,000 miles. To see whether her customers are adhering to this...

A car dealer recommends that transmissions be serviced at 30,000 miles. To see whether her customers are adhering to this recommendation, the dealer selects a sample of 40 customers and finds that the average mileage of the cars serviced is 30,456 miles. The standard deviation of the sample is 1684 miles. By finding the P-value, determine whether the owners are having their transmissions serviced at the 30,000 miles using a 0.10 significance level.