It has been reported that the average time to download the home page from a government website was 0.9 seconds.Suppose that the download times were normally distributed with a standard deviation of 0.3 seconds.If random samples of 36 download times are selected,what is the probability that the sample mean will be less than 0.84 seconds?
A).1151
B).4522
C).8849
D).5478

Question

Quizplus · Accepted Answer

The standard error of the mean is 0.3/sqrt(36) = 0.05. The z-score for 0.84 is (0.84-0.9)/0.05 = -1.2. Using the standard normal distribution table, the probability corresponding to a z-score of -1.2 is approximately 0.1151.

It Has Been Reported That the Average Time to Download