Question

In a certain city, the hourly wage of workers on temporary employment contracts is normally distributed. The mean is $15 and the standard deviation is $3. What percentage of temporary workers earn less than $12 per hour? A. 6% B. 16% C. 26% D. 36%

Answer 1

Knowing the empirical rule and the laws of normal distribution, everything to the left of one standard deviation is equal to 16%.

Answer 2

B. 16%

Explanation:

In the picture attached, the standard normal distribution table is shown.

The value of Z is computed as follows:

Z = (x - μ)/σ

where x is the value of interest ( = 12), μ is the mean ( = 15) and σ is the standard deviation (= 3). Replacing:

Z = (12 - 15)/3 = -1

From the table, the probability is 0.1587, approximately equal to 16%