3. The following problems provide more practice using conditional statements to tabulate and summarize variables. (a) Among unmarried people, what is the fraction of those who were never married before? You should report a number between 0 and 1. (Hint: use the variables, married and never_married.) (b) What is the difference in average hours worked for married and unmarried workers? Please report a positive number. (Hint: use the variables married and hours.) (c) What is the average hours worked for unmarried college graduates with strictly more than 8 years of experience? 2 (Hint: use the variables married, collgrad, tt1_exp, and hours.) (d) Among those living in urban areas, what is the fraction of laborers? Please report a number between 0 and 1. (Hint: use the variables occupation and urban. In addition, missing values should not be counted in your calculation.) (e) Use the variable wagecopy. Among unionized workers, what is the fraction of those who earn strictly more than $6.5 an hour? Please report a number between 0 and 1