1. EXPERIMENTS: PART 3

2. Overview  Goodwin7 and these lecture notes mainly provide a review of key concepts and additional practice  Mastery needed for more challenging concepts on the immediate horizon  Control Groups (we’ll turn to this topic when we get to the clinical research lectures)

3. Review of Experiments  Experiment  Study where a researcher systematically manipulates one variable in order to examine its effect(s) on one or more other variables  Two components Includes two or more conditions Participants are randomly assigned by the researcher Random = Equal odds of being in any particular condition

4. Review of Terminology  Variables: Independent, Dependent, and Extraneous  Designs: Between-group, Within-subject  Terms: Factor, Level  Single-factor, two-level design  Single-factor, multi-level design  Two-factor design (coming soon)  Analyses: t-test, ANOVA (F-test)

5. Review of Terminology  Variables: Independent, Dependent, and Extraneous  Designs: Between-group, Within-subject  Terms: Factor, Level  Single-factor, two-level design  Single-factor, multi-level design  Two-factor design (coming soon)  Analyses: t-test, ANOVA (F-test)

6. Review of Terminology  Variables: Independent, Dependent, and Extraneous  Designs: Between-group, Within-subject  Terms: Factor, Level  Single-factor, two-level design  Single-factor, multi-level design  Two-factor design (coming soon)  Analyses: t-test, ANOVA (F-test) Final section on experiments (e.g., Goodwin8) is very challenging, so need to get these concepts down. Which experimental concepts are most confusing to date?

7. Practice #1 In a randomized controlled trial comparing surgery, medication, and placebo treatments for heart disease, a research team examined how well these treatments improves blood pressure. How many factors? One. Treatment type How many levels? Three. Surgery, medication, and placebo What type of analysis would you use? ANOVA. The IV is categorical and has multiple levels, and the DV is continuous.

8. Practice #2 Participants in a study complete 10 frames of bowling. During half of the frames, participants bowl as quickly as possible. During the other half, participants bowl normally. The DV is number of points (pins knocked down in fast vs. normal condition). How many factors? One. Bowling condition. How many levels? Two. Speed or control. (Doesn’t matter that there are repeats) What type of analysis would you use? t-test. The IV is categorical and has two levels, and the DV is continuous

9. Practice #3 A researcher has each participant complete a survey measure of “Need for Cognition” and compares these scores to GPA. How many factors? Trick question. No categorical variables. How many levels? Trick question. No categorical variables. What type of analysis? Correlational. Both variables are continuous.

10. Practice #4 A researcher wants to study memory span. She examines whether caffeine improves memory over a placebo control, and she also examines male/female gender differences in memory span. How many factors? Two. Type of pill and gender. How many levels? Two for pill (caffeine vs. placebo) and two for gender (male vs. female) Type of analysis? ANOVA because multiple categorical IVs are present