Answer the following questions for each study described below. (1) Is the study primarily an observational study, a correlation study, or an experiment? Why do you give the answer you did? (2) What are the variables involved in the study? For experiments, specify the independent and dependent variables. (3) What might be the hypothesis that the researchers are trying to test?

1.       A researcher is interested in the relationship between caffeine consumption and level of stress. She has participants keep a diary for one week during which they count the number of cups of coffee, tea, and cola-based soft drinks they consume, as well as recording consumption of chocolate and medications that have caffeine as an ingredient. In addition, participants complete a measure of “daily hassles” experienced during the week.

2.       A pair of psychologists are interested in the effects of mood on helping (based on Isen & Levin, 1972). They go to shopping malls and set up observation near telephone booths. Their participants are individuals who use the phone booths when the vicinity is otherwise unoccupied. For half of the participants, the researchers leave a dime to be found in the coin slot of the pay-phone. For all of the participants, when the phone call is completed and the person leaves the telephone booth, a confederate walks by the booth, and drops a file folder full of papers. The researchers watch to see if the participants help pick up the dropped papers.

3.       Researchers (Reifman, Larrick, and Fein, 1988) were interested in the factors causing aggression. They looked at an entire baseball season’s worth of news reports. For each game, they recorded the temperature of the locale, and the number of batters who were hit by pitched balls.

4.       Researchers are interested in influences on self-esteem. Half of the participants used in this study are male, and half are female. Participants are given a set of anagram problems to solve in a five minute time limit. Half are randomly assigned to receive very easy anagrams, and half are given difficult ones. After completing as many of the anagrams as they can, participants are given a questionnaire labeled “Thoughts and Feelings Questionnaire” that is really a measure of self-esteem.

5.       Researchers are interested in what determines how easily people are persuaded. Half of the participants used in this study are male, and half are female. During the session, participants rate their attitude towards an increase in fees that has been proposed at their school. Following this, they listen to a persuasive message providing strong arguments in favor of the fee increase. Finally, they re-rate their attitude towards the proposed fee.