1 Way ANOVA

Question 1

How does running an ANOVA reduce the risk of family-wise errors, compared to doing lots of t tests?

Answer 1

ANOVA simultaneously accounts for all comparisons within the same analysis, so type 1 error rate stays at 5%.

Question 2

Define single factor ANOVA.

Answer 2

Analysis of one IV that may have multiple levels.

Question 3

What is the total variance composed of?

Answer 3

Experimental variance and random variance.

Question 4

How do you calculate an F ratio?

Answer 4

Experimental variance/ Random variance.

Question 5

What does a large F value suggest?

Answer 5

Lots of variance is explained by the experimental manipulation.

Question 6

What does total sum of squares refer to in independent 1 way ANOVA?

Answer 6

How far participants are from the overall mean.

Question 7

What does model sum of squares refer to in independent 1 way ANOVA?

Answer 7

Between groups variability: How far each group mean is from the overall mean.

Question 8

What does error sum of squares refer to in independent 1 way ANOVA?

Answer 8

Within groups variability: How participants are from their group mean.

Question 9

How do you calculate model mean squares in independent 1 way ANOVA?

Answer 9

SSmodel/ dfmodel.

Question 10

How do you calculate error mean squares in 1 way ANOVA?

Answer 10

SSerror/ dferror.

Question 11

What do we know when an ANOVA is significant?

Answer 11

There are differences, but we do not between which group/ condition yet.

Question 12

What are the five parametric assumptions required to carry out an independent ANOVA?

Answer 12

IV is categorical, DV is continuous, independence of observations, normality and homogeneity of variance.

Question 13

How do you check for normality in your data?

Answer 13

Combination of tests of normality table (Shapiro-Wilk), Q-Q plots, Skewness and Kurtosis.

Question 14

How do you check for homogeneity of variance in you data?

Answer 14

Levene’s test.

Question 15

What is homogeneity of variance?

Answer 15

Similar variance within groups across different groups.

Question 16

When do you conduct planned comparisons?

Answer 16

When specific hypotheses and comparisons were decided on prior to seeing the data.

Question 17

What are the 5 rules of orthogonal comparisons?

Answer 17

Only compare 2 chunks of variation, positive weighted groups compared to negative weighted, sum of weights must be zero, groups not involved must be coded zero, and weights assigned to one chunk of variation must be equal to weights assigned to the other.

Question 18

Which planned comparisons do you run when you are comparing more than 2 chunks of variation?

Answer 18

Non-orthogonal.

Question 19

What is required when conducting non-orthogonal planned comparisons?

Answer 19

Bonferroni corrections, to be conservative and account for correlated p-values.

Question 20

When do you conduct post-hoc comparisons?

Answer 20

To explore all possible differences after seeing the data.

Question 21

Which correction should you choose for post-hoc comparisons when Levene’s test was significant?

Answer 21

Games-Howell.

Question 22

Which correction should you choose for post-hoc comparisons when there is a SLIGHTLY different number of groups?

Answer 22

Gabriel

Question 23

Which correction should you choose for post-hoc comparisons when there is a VERY different number of groups?

Answer 23

Hochberg’s GT2.

Question 24

Which correction should you choose for post-hoc comparisons when you are doing MANY pairwise comparisons?

Answer 24

Tukey.

Question 25

Which correction should you choose for post-hoc comparisons when you are doing FEW pairwise comparisons?

Answer 25

Bonferroni.

Question 26

What does total sum of squares refer to in repeated measures 1 way ANOVA?

Answer 26

How far participants are from the overall mean.

Question 27

What does condition sum of squares refer to in repeated measures 1 way ANOVA?

Answer 27

Between groups variability: How far each condition mean is from the overall mean.

Question 28

What does within GROUPS sum of squares refer to in repeated measures 1 way ANOVA?

Answer 28

Within groups variability: How participants are from the condition mean.

Question 29

What does within SUBJECTS sum of squares refer to in repeated measures 1 way ANOVA?

Answer 29

How far each participant’s mean is from the overall mean.

Question 30

What does within error sum of squares refer to in repeated measures 1 way ANOVA?

Answer 30

SSwithin - SSsubjects of SStotal - SScondition - SSsubjects.

Question 31

How do you calculate condition mean squares in repeated measures 1 way ANOVA?

Answer 31

SScondition/ dfcondition.

Question 32

What are the four parametric assumptions required to carry out a repeated measures ANOVA?

Answer 32

IV is categorical, DV is continuous, normality and sphericity.

Question 33

How do you check for sphericity in your data?

Answer 33

Mauchly’s test.