Statistics and Probability

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 54 and a standard deviation of 9. Using the empirical rule (as presented in the book), what is the approximate percentage of daily phone calls numbering between 45 and 63?

Do not enter the percent symbol.

ans =

Answer 1

I'm unsure about your particular book but here is a graph of the normal curve with percentages for various standard deviations.

You can see that up one standard deviation and down one standard deviation encompasses approximately 68% of the population and that is what your situation is (54 + 9 = 63 and 54 - 9 = 45).