Suppose the time it takes for a purchasing agent to complete an online ordering process is normally distributed with a mean of 8 minutes and a standard deviation of 2 minutes.Suppose a random sample of 25 ordering processes is selected.What is the probability that the sample mean will be less than 7.5 minutes?
A)0.3944
B)0.1056
C)0.2114
D)0.4013
E)0.8944

Question

Quizplus · Accepted Answer

The standard error of the mean is 2/sqrt(25) = 0.4. The z-score for 7.5 is (7.5-8)/0.4 = -1.25. Using the standard normal distribution table, the probability of a z-score being less than -1.25 is approximately 0.1056.

Suppose the Time It Takes for a Purchasing Agent to Complete