ANOVA

Question 1

What does ANOVA stand for?

Answer 1

-Analysis of variance

Question 2

Describe ANOVA test

Answer 2

-Extension of T-test
-Allows us to test whether 3 (or more) population means are the same, without reducing the power
-Compare multiple conditions in a single. powerful test

Question 3

What is the test statistic for ANOVA?

Answer 3

-Invented by Fisher
-Test statistic is F

Question 4

What is alpha?

Answer 4

-Value so that the test can be considered a true test
-Tends to be 5%, overall likelihood of error becomes 15% which is too high

Question 5

What are the assumptions of ANOVA?

Answer 5

-Scores were sampled randomly
-Independent
-Roughly normal distribution
-Roughly equal number of ppts in groups
-Roughly equal variance for each condition

Question 6

What is the aim of ANOVA?

Answer 6

-Compares amount of variance explained by the experiments with the variance that is unexplained
-Explained = variance between groups
-Unexplained = variance within groups

Question 7

Describe the degrees of freedom used in ANOVA

Answer 7

-Associated with both variance values
-Degrees of freedom between conditions
-Residual degrees of freedom

Question 8

Describe the pairwise comparisons

Answer 8

-Tells us whether groups differ or not
-Run multiple comparisons
-Some are ‘planned’ comparisons and some are ‘post-hoc’ comparisons
-Tend to use ‘Bonferroni correction’ - divide alpha by number of tests

Question 9

What are the versions of ANOVA?

Answer 9

-Analysis of variance
-Multivariate analysis of variance
-Analysis of covariance

Question 10

Describe the analysis of variance

Answer 10

-One way or one factor
-Multi factor

Question 11

Describe the multivariate analysis of variance

Answer 11

-Extension of ANOVA for multiple d.v.s

Question 12

Describe the analysis of covariance

Answer 12

-Extension of ANOVA to handle continuous variables e.g. correlations