The problem is to understand the effect of the average amount of tobacco smoked and the cause of death on the male death rates per 1000.
A data frame with 15 observations on the following 5 variables.
Between 1-14 grams
Between 15-24 grams
More than 25 grams
Velleman, Paul F., and David C. Hoaglin. Applications, basics, and computing of exploratory data analysis. Vol. 142. Boston: Duxbury Press, 1981.