Identify the appropriate hypothesis test for each of the following research situations.
a. A researcher conducts a between-subjects study to determine whether there is a significant difference in problem-solving ability between older adults who are generally happy and those who are generally unhappy.
b. A researcher gives a questionnaire to a group of 30-year-old married adults, including questions to measure the stability of their own marriages and the stability of their parents’ marriages. The researcher would like to know whether the two variables are related.
c. A researcher obtains a sample of 100 college students between 18 and 21 years old and a similar sample of 100 young adults who have no college experience. The researcher would like to know if there is a difference in the proportion of registered voters for the two groups.