Question

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 1400 miles. What is the probability a certain tire of this brand will last between 56,850 miles and 57,300 miles?

Answer 1

Answer:-

Given that:-

mean

Standard deviation

to find probability a particular tire of this brand will last longer than 56,850 i.e., P(X>57,300) we use z-score & z - score is given as

Here, X=57,300  

Calculate

Z=-1.9285

Hence,

  

the probability of a particular tire of this brand will last longer than 57300 miles is 0.9732.