PSY 205 Homework: Measurement and Experiments
Due Friday, 9/29
· Answer the questions on a separate piece of paper.
· Staple your homework together if there is more than one page.
· Homework must be typewritten to receive credit.
· You must do your own work – do not work on the assignment with another student.
· You do not need to re-type the questions; just number each answer appropriately (A1, B1, etc.)
· Each question is worth 2 points (total=32)
A. A researcher examined whether college students were better at remembering certain categories of words than others. All participants were shown 12 words and were then asked to write down as many as they could recall. The researcher randomly assigned participants to one of 3 conditions: 25 participants were shown words that were professions (e.g. waiter, secretary); 25 different participants were shown words that were foods (e.g. apple, broccoli); and a third group of 25 participants were shown words that were animals (e.g. dog, zebra).
1. Clearly identify the IV
2. Clearly identify the levels of the IV (conditions).
3. What is the level/scale of measurement of the IV? Explain your answer.
4. Clearly identify the DV.
5. What are two control variables that the researcher should have in this study?
6. Is this a between-groups or within-groups design? Explain.
7. Students will vary in how good their memories are. What kind of variable is this? Explain.
8. All of the students were from the same university. What kind of validity does this limit? Explain.
9. The “profession” group was tested in the morning, the “food” group at lunchtime, and the “animal” group in the evening. What kind of variable is this? Explain.
B. Dr. Hershey wants to study the impact of eating chocolate on problem solving ability. She plans to offer people either no chocolate, 1 piece of chocolate, 2 pieces of chocolate, or 3 pieces of chocolate, and then have each person take a test involving logic problems. She expects that people who consume more chocolate will be able to solve more of the problems. She has 60 people signed up to participate in her study.
1. What is Dr. Hershey’s operational definition of “problem solving ability?”
2. What is the level/scale of measurement of the DV? Explain your answer.
3. What are two control variables that Dr. Hershey should have in this study?
4. Participants will vary in how much they like chocolate. What kind of variable is this? Explain.
5. Describe how Dr. Hershey could run this study using a within-groups design.
6. How might demand characteristics influence the outcome if a within-groups design is used?
7. Describe how Dr. Hershey could use a Latin Square design in her study.