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A tire company claims that the lifetimes of its tires average 5.00E4 miles. The standard
deviation of tire lifetimes is known to be 5,000 miles. You sample 100.0 tires and will test
the hypothesis that the mean tire lifetime is at least 5.00E4 miles against the alternative
that it is less. Assume, in fact, that the true mean lifetime is 4.95E4 miles.
You are given the opportunity to sample more tires. How many tires should be sampled in total so that the
power is 0.80 if the test is made at the 5% level?
The total number of tires that should be sampled is