The data set in ALCOHOL contains information on a sample of men in the United States. Two key variables are self-reported employment status and alcohol abuse (along with many other variables). The variables employ and abuse are both binary, or indicator, variables: they take on only the values zero and one.

(i) What percentage of the men in the sample report abusing alcohol? What is the employment rate?

(ii) Consider the group of men who abuse alcohol. What is the employment rate?

(iii) What is the employment rate for the group of men who do not abuse alcohol?

(iv) Discuss the difference in your answers to parts (ii) and (iii). Does this allow you to conclude that alcohol abuse causes unemployment?