Using the empirical rule (as presented in the book), what is the approximate percentage of daily phone calls numbering between 59 and 69?

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 64 and a standard deviation of 5. Using the empirical rule (as presented in the book), what is the approximate percentage of daily phone calls numbering between 59 and 69?

Answer 1

68%

59 < x < 69 is within 1 standard deviation from the mean

64-59 = 5

69-64 = 5

5 = 1 standard deviation

empirical rule is 68-95-99.7 for 1,2 and 3 standard deviations from the mean