Instructions: Show all steps of your calculations for full credit. For word problems, answer in your own words. Please clearly indicate your final answer (e.g., by putting a box around it).

1.

For each of the following, identify whether it is a correlational study or an experiment.

A. A researcher is interested to find out whether the size of a serving dish influences the amount of food people eat. He gave half the diners at a buffet a small plate and the other half a large plate, and weighed the amount of food the participants served themselves.

B. A researcher recruited 120 smokers who filled out a questionnaire about their exercise habits. The researcher is interested to find out if people who smoke more are less likely to exercise on a regular basis.

c. A researcher uses data from income tax returns to examine whether income is associated with charity donations.

2.

During the 2013-2014 NHL playoffs, Evgeni Malkin scored 6 goals, Sidney Crosby scored 1, Chris Kunitz scored 3, Kris Letang scored 2, and Jussi Jokinen scored 7. Compute the following (show all the steps):

a.

b. ^2

c. ()^2

3. Professor Jackson wants to know whether test performance is influenced by the testing format. To do this, he gave half his students a multiple-choice test and the other half a fill-in-the-blank test. He then compared the number of questions that the two groups of students answered correctly on the test.

A. What is the independent variable?

B. What scale of measurement is the independent variable measured on?

C. What is the dependent variable?

D. What scale of measurement is the dependent variable measured on?

4. Use the summation notation to express each of the following:

A. Add up all the scores, then subtract 1 from the sum.

B. Add 5 to each score, then sum all the values.

C. Subtract 25 from each score, square the resulting values and then add up all the squared values.

5.. In a study examining the effect of alcohol on reaction time, half of the randomly assigned participants drank a glass of juice laced with alcohol, while the other half drank regular juice. They then had their reaction time tested, and the researchers found that the group that drank alcohol appeared to have a slower average reaction time than the group that did not drink alcohol. Describe the two possible reasons for the observed difference in reaction time.

6. An educational research institute is interested in understanding the views of university professors in the United States on educational technologies. To accomplish this, the researchers surveyed 300 professors from across the country. In this example, identify the population and the sample.

7. A study found that pet owners tend to be happier. One possible explanation is that having the companionship of a pet causes happiness. Describe two alternative causal relationships that can also explain the link between pet ownership and happiness. The causal direction of the two alternative explanations must be different from one another.