2 way factorial anova

Question 1

what is a two way independent anova?

Answer 1

• two way - 2 independent variables - three way - 2 independent variables
• different participants in all conditions
• several independent factors known as factorial design

Question 2

rationale for using a factorial anova?

Answer 2

• high variability within a group
• statistically controls for known variance - more likely a significant effect could be detected
• Will analyse the effects of individual factors (main effects) and the combined effects of factors (interaction effects)

Question 3

list some factors that distinguish between subject effects?

Answer 3

• gender
• socio-economic group
• positional role in sport
• age in cross sectional study

Question 4

list some factors that identify within subject effects?

Answer 4

• time of day
• pre and post experimental
• experimental / control is crossover designs
• age in longitudinal study

Question 5

what is a two way repeated measures anova?

Answer 5

• number on independent variables - 2 - two way - 3 - way

- the same participants in all conditions

Question 6

what is a main effect and interaction ?

Answer 6

• main effect - Determine if each of the main factors has an influence on some numerical dependent variable when controlling variance due to the other factor
• interaction - Determine if the combined effects of the two factors has an influence on the dependent variable of interest (interaction)

Question 7

How does the significance of the interaction influence the post hoc application ?

Answer 7

• no significant interaction post hoc tests can be applied to each individual factor as a whole
• Significant interaction post hoc tests need to be applied to a factor for each level of the factor it interacts with

Question 8

what are the assumptions for a between between factorial anova?

Answer 8

• similar to one way anova test
• it is robust to violations of normality as long as the largest SD of any factor combination does not exceed double the value of the smallest SD

Question 9

how is the variation split in a 2 way factorial anova?

Answer 9

• SST = SSm + SSr
• SSm is comprised of the variance explain by variable a, variance explained by variable b and variance explained by the interaction off variable a and b.

Question 10

what are the assumptions for a two way repeated measures anova?

Answer 10

• similar to between between factorial anova
• where within within effects are measured at more than two levels, the data should, satisfy the assumptions of sphericity