In the United States, the estimated annual probability that a woman over the age of 35 dies of lung cancer equals .001304 for current smokers and .000121 for nonsmokers (M. Pagano and K. Gauvreau, Principles of Biostatistics, Belmont, CA: Duxbury Press, 1993, p. 134).

a. Calculate and interpret the difference of proportions and the relative risk. Which of these measures is more informative for these data? Why?

b. Calculate and interpret the odds ratio. Explain why the relative risk and odds ratio take similar values.