Identify all variables in these research projects and classify them by their level of measurement. Which variables are independent and which are dependent?
a. A graduate student asks 500 female students if they have experienced any sexual harassment on campus. Each student is asked to estimate the frequency of these incidents as either "often," "sometimes," "rarely," or "never." The researcher also gathers data on age and major to see if there is any connection between these variables and the frequency of sexual harassment.
b. A supervisor in the Solid Waste Management Division of city government is assessing two different methods of trash collection. One area of the city is served by trucks with two-man crews who do "backyard" pickups, and the rest of the city is served by "high-tech" single-person trucks with curbside pickup. The assessment measures include the number of complaints received from the two different areas over a six-month period, the amount of time per day required to service each area, and the cost per ton of trash collected.
c. The adult bookstore near campus has been raided and closed by the police. Your social research class has decided to poll a sample of students to find out if he or she supports or opposes the closing of the store, how many times each has visited the store, and if he or she agrees or disagrees that "pornography causes sexual assaults on women." The class also collects information on the sex, age, religion, political philosophy, and major to see if opinions are related to these characteristics.
d. For a research project in a political science course, a student has collected information about the quality of life and the degree of political democracy in 50 nations. Specifically, she used infant mortality rates to measure quality of life and the percentage of all adults who are permitted to vote in national elections as a measure of democratization. Her hypothesis is that quality of life is higher in more democratic nations.
e. A highway engineer wonders if a planned increase in the speed limit on a heavily traveled local avenue will result in any change in the number of accidents. He plans to collect information on traffic volume, the number of accidents, and the number of fatalities for the six-month periods before and after the change.
f. Students are planning a program to promote safe sex and awareness of other health concerns for college students. To measure the effectiveness of the program, they plan to give a survey measuring knowledge to a random sample of students before and after the program.
g. States have drastically cut their budgets for mental health care. Will this increase the number of homeless people? A researcher contacts a number of agencies serving the homeless in each state and develops an estimate of the size of the population before and after the cuts.
h. Does tolerance for diversity vary by race or ethnicity? Samples of white, black, Asian, Hispanic, and Native Americans have been given a survey that measures their interest in and appreciation of cultures and groups other than their own.