45. In the United States, the estimated annual probability that a woman over the age of 35 dies of lung cancer equals 00130 for current smokers and .00012 for nonsmokers (M. Pagano and K Gauvreau, Principles of Biostatistics, Belmont, CA: Duxbury Press. 1993. p. 134).

a) Calculate and interpret the difference between smokers and nonsmokers in the propor- uons who die of lung cancer in a given year. Interpret. Are the proportions similar. or quite different, for the two groups?

b) Another way to compare the two proportions is through their ratio. The ratio equals 10 when the proportions are equal, and ratios farther from 1.0 represent larger differences between the groups. Calculate the ratio of the proportions for smokers and nonisinokers, and interpret. According to this ineasure, are the proportions similar. or quite different. for the two groups? (Note The ratio of proportions is also called the relative risk It is often more iclevant than the difference of proportions when both proportions are close to zero, )