Question

Yoonie is a personnel manager in a large corporation. Each month she must review 16 of the employees. From past experience, she has found that the reviews take her approximately four hours each to do with a population standard deviation of 12 hours. (1) What is the mean time to complete one review? QUESTION 2 (2) What is the standard deviation to complete one review? QUESTION 3 (3) What is the probability that one review will take Yoonie from 3.5 to 4.25 hours? (Round to 3 decimal places) QUESTION 4 What is the mean time for Yoonie to complete the 16 reviews? QUESTION 5 (5) What is the standard deviation for her to complete the 16 reviews?

Answer 1

Solution: Given that mean = 4, sd = 1.2

(1) the mean = 4 hours

(2) sd = 1.2

(3) P(3.5 < X < 4.25) = P((3.5-4)/1.2 < (X-mean)/sd < (4.25)/1.2)
= P(-0.4167 < Z < 3.5417)
= 0.6626

(4) for = n = 16 μx = μ = 4

(5) for = n = 16 σx = σ/sqrt(n) = 1.2/sqrt(16) = 0.3