Mileage Tests Were Conducted on a Randomly Selected Sample of 100

Multiple Choice

Mileage tests were conducted on a randomly selected sample of 100 newly developed automobile tires. The average tread life was found to be 80,000 kilometres with a standard deviation of 5,600 kilometres. What is the best estimate of the average tread life in miles for the entire population of these tires?

A) 80,000
B) 5,600
C) (80,000/100)
D) (5,600/100)