Two-way ANOVA

Question 1

Two-way ANOVA

Answer 1

• two or more independent variables
• compares groups on two categorical levels
• includes interaction effects between groups
• more information, more efficient and reduces residual variation.

Question 2

Degrees of freedom

Answer 2

• DFAB = (levelsA - 1) (levelsB - 1)

Question 3

F test

Answer 3

• if significant = look at the means to uncover type of interaction.
• factors: independent variables
• conditions: different combinations we get when we cross factors.
• p-value tells us if its significant

Question 4

Interaction effects on line chart

Answer 4

• interactions shows through crossing over of line
• no interaction = parallel lines

Question 5

Decision

Answer 5

• if F is bigger than the critical F = significant = p-value is below 0.05.
• if F is smaller than the critical F = not significant = p-value is above 0.05.

Question 6

Mauchly’s test of sphericity

Answer 6

• if p-value is less than 0.05 = assumption is violated and there are significant differences.
• spericity can only be violated if there is a difference in atleast 2 of 3 conditions

Question 7

Repeated measures design

Answer 7

• same variable, multiple measures, same people, different points in time within groups.

Question 8

Mean

Answer 8

• overall mean: grand mean (mean of every score)
• person mean: mean of the same person in all conditions

Question 9

Degrees of freedom in table

Answer 9

• DFm = numerator column
• DFr = denominator column