Lecture 8: Basic experimental Designs

Question 1

Different participants are assigned to each level or condition of the IV.

Answer 1

Between-subjects designs

Question 2

The same group of participants are assigned to each level or condition of the IV.

Answer 2

Within-subjects designs

Question 3

What do between-subjects design require/makes beneficial and what is the risk? (3pts)

How do you reduce this risk? (3pts)

Answer 3

• Require large samples, random assignment to conditions
• At risk for selection differences
• Reduce the risk through random assignment to conditions, pretest-posttest design, matched pairs

Question 4

What do within-subjects designs require/makes beneficial and what is the risk/sensitive to? (3pts) How do you reduce this risk? (1pt)

Answer 4

-Require fewer participants, remove the influence of individual differences across conditions
- Sensitive to order effects
- reduce the risk through counterbalancing the order of IV levels

Question 5

DV measured both before and after experimental manipulation of IV. Can compare pretest scores across groups and ensure no pre-existing differences.

Answer 5

Pretest-posttest design