Wrong Number. A classic study by F. Thorndike on the number of calls to a wrong number appeared in the paper “Applications of Poisson’s Probability Summation” (Bell Systems Technical Journal, Vol. 5, pp. 604–624). The study examined the number of calls to a wrong number from coin-box telephones in a large transportation terminal. Based on the results of that paper, we obtained the following percent distribution for the number of wrong numbers during a 1-minute period.

Wrong 0 1 2 3 45678 Percent 17.2 30.5 26.6 15.1 7.3 2.4 0.7 0.1 0.1

a. Construct a relative-frequency histogram of these wrong-number data.

b. Based on your histogram, do you think that the number of wrong numbers from these coin-box telephones is approximately normally distributed? Explain your answer.

Working with Large Data Sets