Exhibit 6-8
The life expectancy of a particular brand of tire is normally distributed with a mean of 40,000 and a standard deviation of 5,000 miles.
-Refer to Exhibit 6-8. What is the probability that a randomly selected tire will have a life of at least 47,500 miles?
A)0.4332
B)0.9332
C)0.0668
D)0.4993

Question

Quizplus · Accepted Answer

To find the probability that a tire lasts at least 47,500 miles, calculate the Z-score: Z = (47,500 - 40,000) / 5,000 = 1.5. Using the standard normal distribution table, the probability of Z being less than 1.5 is approximately 0.9332. Therefore, the probability of a tire lasting at least 47,500 miles is 1 - 0.9332 = 0.0668.

Exhibit 6-8 The Life Expectancy of a Particular Brand of Tire Is