One-way ANOVA:
1. The one-way ANOVA is the preferred test for a study design with one _nominal___-level dependent variable (DV) and one __scale___-level independent variable (IV).
2. If an IV has more than two levels, why canyou not just run many t tests on the same variable?You have a greater chance of getting a false positive, or rejecting the null hypothesis when the null hypothesis is true. Why do you use the one-way ANOVA instead?
3. What is the formula for calculating the F ratio in a one-way ANOVA? F = MSbg / MSwg How would you describe this formula in words?This formula evaluates whether the group means on the dependent variable differ signifianly from each other. This is an overall (analysis of variance test) is conducted to assess whether means on a dependent variable are significantly differnet among groups.
4. You can compare the t and F statistics by looking at their numerators. What kind of comparison is being made in the numerator of each statistic?
5. Define between-groups variance and within-groups variance. How are they different? Which one do we want to be larger in the ANOVA?
6. What kinds of situations/studies would require a one-way between-groups ANOVA, and what kinds would require a one-way within-groups ANOVA?
7. What are the assumptions of a one-way ANOVA?
8. How do you calculate all of the different degrees of freedom in a one-way ANOVA (i.e., what are the formulas)?
9. Can the F statistic ever be negative?
10. What is the grand mean?
11. A researcher runs a one-way ANOVA, and the independent variable has 3 levels. The F ratio turns out to be significant (p<.05). What, if anything, can you say about the difference between the individual levels of the IV at this point? What steps do you need to take to better understand the difference between the different levels?
12. What does R2 stand for? Know Cohen's conventions for this variable.
13. Be able to recognize the names of post hoc tests.
14. Name the different kinds of degrees of freedom in a one-way within-groups ANOVA. Which of these does not exist for the one-way between-groups ANOVA?
15. Define "order effects" for a within-groups ANOVA.
Two-way ANOVA:
1. What was the main finding of the Zinman and Zitzewitz study described in your text?
2. The two-way ANOVA is used when the study has one _______-level dependent variable and two or more ______-level independent variables.
3. Define a factor as it relates to the two-way ANOVA.
4. How many hypotheses are there in a two-way ANOVA? How many F ratios are there in a two-way ANOVA?
5. Review the terminology of the two-way ANOVA.
a. Two-way ANOVA = ____ independent variables (IV's) or factors
b. Three-way ANOVA = ____ IV's/factors
c. Five-way ANOVA = _____ IV's/factors
d. 2x2 between-groups ANOVA = ___ IV's/factors with ___levels each
e. 3x2 within-groups ANOVA = ___IV's/factors, one with ___ levels and one with ___ levels
6. If you constructed a table for a 2x2 ANOVA, how many cells would it have? A 3x3 ANOVA?
7. Define a main effect and an interaction. How many main effects and interactions are there in a two-way ANOVA?
8. What are marginal means?
9. What are the formulas for all of the degrees of freedom values involved in a two-way ANOVA?
10. Be ready to read a research scenario and decide the type of ANOVA (2x2, 4x2, etc.), what the factors are, or calculate degrees of freedom given different values.