The mean number of words per minute WPM read by sixth grader

The mean number of words per minute (WPM) read by sixth graders is 89 with a standard deviation of 16. If 66 sixth graders are randomly selected, what is the probabilty that the sample mean would be greater than 92.25.

(92.25-89)/(16/sqrt(66))= 1.65

P(Z> 1.65)

I don\'t know where to go after that. What is P?

Solution

p(z>1.65) = 1 - p(z<=1.65)

Looking at the z-table

p(z <= 1.65) = .9505

Thus,

1 - .9505 = .0495 = p(z>1.65)