Table 5-18 on the textbook's Web site contains data on average life expectancy for 40 countries. It comes from the World Almanac and Book of Facts, 1993, by Pharos Books. The independent variables are the ratio of the number of people per television set and the ratio of number of people per physician.
a. Try fitting a linear (LIV) model to the data. Does this model seem to fit well?
b. Create two scatter grams, one of the natural log of life expectancy versus the natural log of people per television, and one of the natural log of life expectancy versus the natural log of people per physician. Do the graphs appear linear?
c. Estimate the equation for a log-linear model. Does this model fit well?
d. What do the coefficients of the log-linear model indicate about the relationships of the variables to life expectancy? Does this seem reasonable?