We are given:
45,00 miles is the actual tread life of the tire.
The standard deviation is 3,000 miles
The mean of the tire life is 45,000 miles
The range of the tread life is:
45,000 - 3,000 = 42,000 miles
to
45,000 + 3,000 = 48,000 miles
The probability that the tire tread life will fall between 44,500 and 47,500 miles can be determined by testing several tire samples.
