A tire manufacturer advertises that their brand of radial tires has a mean life of 40,000 miles with a population standard deviation of 1,500 miles. A consumer research team decides to investigate this claim after receiving several complaints from people who believe the advertisement is false and that the mean life of 40,000 miles is too high. The research team tests 100 of these radial tires and obtains a sample mean tire life of 39,750 miles. Is the advertisement legitimate