Tipping. In the article “Are Christian/Religious People Poor Tippers?” (Journal of Applied Social Psychology, Vol. 43, Issue 5, pp. 928–935), M. Lynn and B. Katz report that, for customers who receive bad service, the mean percentage tip is 8.56% of the bill with a standard deviation of 5.37%. Let x represent the percentage of the bill that a customer tips when he or she receives bad service.

a. What percentage of tips for bad service are at least 0%?

b. Assuming that x is approximately normally distributed, use normalcurve areas to determine the approximate percentage of tips for bad service that are at least 0%.

c. Based on your results from parts

(a) and (b), do you think that the percentage of the bill that a customer tips when he or she receives bad service is approximately a normally distributed variable? Explain your answer.
Extending the Concepts and Skills