The tread life of a particular brand of tire is a random variable best described by a normal distribution with a mean of 60,000 miles and a standard deviation of 2500 miles. What is the probability a certain tire of this brand will last between 54,750 miles and 55,500 miles?
A) .0180
B) .4920
C) .9813
D) .4649

Question

Quizplus · Accepted Answer

The Z-scores for 54,750 and 55,500 miles are -2.1 and -1.8, respectively. The probability between these Z-scores is approximately 0.0180.

The Tread Life of a Particular Brand of Tire Is