Manova

Question 1

what is manova

Answer 1

multivariate analysis of variance

Question 2

when is this used

Answer 2

used when have one IV and many dependent variables

Question 3

give an example of this type of anova

Answer 3

effect of pet ownership on mental health (IV) mental health cons= depression, anxiety ocd etc. (many DV’s)

Question 4

what is the issue with having lots of DV’s in an experimental design

Answer 4

increase chance of type 1 errors (false positives)

Question 5

what do a manova do

Answer 5

assess whether IV has effects on variables taken together

Question 6

If there is an effect on variables together what do you do next

Answer 6

look at the second part of MANOVA, which aspects of mental health does it specifically effect- analyses individual effects

Question 7

what are the assumptions of a manova

Answer 7

usual anova assumptions
iv- always between subjects
Levenes for homogeneity calculate each DV (non-signif wanted)
box test- tests equal in covariances matrices
homogeneity tests

Question 8

explain the two homogeneity of variance test manovas produce

Answer 8

1. box test - equality of covariances in matrices, (one test related to all. not signif = p value taken from multivariate box in output is reliable
2. levene’s test for equality of error variances (homogeneity) (sep tests for each DV)
   want it to be non signif p > .05 - not sig = each p value for each Dv taken from between subs contrast box = reliable

Question 9

explain what to do with the output of an anova

Answer 9

gives multivariate test- asses whether IV has effect on DV’s (overall)
gives- F value, degrees of freedom and p value (like anovas)

Question 10

what 4 other measures does the output give

Answer 10

1. Pillai’s Trace
2. Wilks Lambda
3. Hotelling’s Trace
4. Roy’s Largest Root
   w/ 2 levels of IV doesn’t matter which is used f value = identical

Question 11

what happens when you add another level of the IV

Answer 11

depends on data (variances etc) which post hoc test is used