The number of miles that regular tires last has a Normal distribution with a mean of 50,000 miles and a standard
deviation of 8,200 miles.
If a random sample of 4 tires are selected, the probability
that the mean number of miles they last is more than
60,000 miles is 0.0075.
Is there convincing evidence that the mean number of
miles for all regular tires is greater than 60,000 miles?
___,it is, to randomly select 4 tires and
obtain a sample mean of greater than 60,000 miles if
the true mean of the population is 50,000 miles.