Costco installs automobile tires on a first-come first-serve basis. The total time a customer needs to wait for the installation to be completed follows the normal distribution with a mean time of 106.3 minutes and a standard deviation of 18.5 minutes. What is the probability that a randomly selected customer will wait more than 125 minutes for his or her tires to be installed?

Question

Quizplus · Accepted Answer

To find the probability that a customer waits more than 125 minutes, we calculate the z-score: z = (125 - 106.3) / 18.5 ≈ 1.01. Using the standard normal distribution table, the probability of z being less than 1.01 is approximately 0.8438. Therefore, the probability of waiting more than 125 minutes is 1 - 0.8438 = 0.1562.

Costco Installs Automobile Tires on a First-Come First-Serve Basis