In a midsize company the distribution of the number of phone

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 36 and a standard deviation of 4. Using the empirical rule (as presented in the book), what is the approximate percentage of daily phone calls numbering between 32 and 40?

Solution

Mean number of phone calls answered each day by each of the 12 receptionists = 36

Standard deviation of the distribution = 4

No of receptionists n = 12

The empirical rule states that 68% will fall within the first standard deviation, 95% within the first two standard deviations, and 99.7% will fall within the first three standard deviations of the mean

percentage of daily phone calls numbering between 32 and 40

32 and 40 are 1 standard deviation from the mean {36 - 4 = 32 and 36 + 4 = 40}

Ans) 68% of the daily phone calls falls between 32 and 40