The average time taken for your Internet service provider to remotely resolve a trouble ticket has a Normal distribution, with a mean of 4.3 hours and a standard deviation of 3.1 hours. What percent of the time can you expect to wait longer than a full (8-hour) business day for a resolution?
A)11.7%
B)15.7%
C)88.3%
D)100%

Question

Quizplus · Accepted Answer

To find the percentage of time you can expect to wait longer than 8 hours, you calculate the Z-score for 8 hours using the formula Z = (X - μ) / σ, where X is 8 hours, μ is the mean (4.3 hours), and σ is the standard deviation (3.1 hours). The Z-score is (8 - 4.3) / 3.1 = 1.19. Looking up this Z-score in a standard normal distribution table or using a calculator, you find that the area to the left of this Z-score is approximately 88.3%, meaning the area to the right (the percentage of time you wait longer than 8 hours) is 100% - 88.3% = 11.7%.

The Average Time Taken for Your Internet Service Provider to Remotely