Standard Normal Distribution

Question

In a mid-size company, the distribution of the number of phone calls answered each day by each of the 12 receptionists is bell-shaped and has a mean of 60 and a standard deviation of 3. Using the empirical rule, what is the approximate percentage of daily phone calls numbering between 54 and 66?

Answer 1

47 1/2 %

54 is 2 standard deviations below the mean

by the empirical rule 95% fall within 2 standard deviations from the mean which would be 54 to 66

54 to 60 is half 95 or 95/2 = 47.5%