Refer to the previous exercise. In each case, state the null and alternative hypotheses.
a. Researchers want to know if there is a relationship between having graduated from college or not and voting in the last presidential election, for all registered voters over age 25.
b. Researchers want to know if there is a relationship between smoking (either partner smokes) and divorce for people who were married between 1990 and 2000.
c. Researchers classify midsize cities in the United States according to whether the city’s median family income is higher or lower than the median family income for the state in which the city is located. They want to know if there is a relationship between that classification and airport availability, defined as whether or not one of the 30 busiest airports in the country is within 50 miles of the city.