Question

A law firm has open several positions for professional typists. The number of words per minute (wpm) typed by the group of applicants follows a normal distribution with mean 67 wpm and a standard deviation of 9 wpm.

What should be the limit if only the top 15% are to be eligible? Round your answer to the nearest whole word.

Answer 1

Given that,  

mean = = 67

standard deviation = = 9

Using standard normal table ,

P(Z > z) = 15%

1 - P(Z < z) = 0.15

P(Z < z) = 1 - 0.15 = 0.85

P(Z < 1.04 ) = 0.85

z = 1.04

Using z-score formula

x = z * +

x = 1.04* 9 + 67= 76

Should be the limit if only the top 15% are to be eligible is 76 wpm.