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)

Question

Quizplus · Accepted Answer

Since the question is asking for the average tread life in miles for the entire population of tires, we need to convert the given metric of kilometres to miles. The conversion factor is 0.621371192, which means that 1 kilometre is equal to 0.621371192 miles. Therefore, the best estimate for the average tread life in miles would be 80,000 x 0.621371192 = 49,709.375 miles, which is closest to option A, 80,000.

Mileage Tests Were Conducted on a Randomly Selected Sample of 100