Testing for the interaction of Gender on Type (grouping variable, group A & B) for a 'Test' score -
model.lm <- lm(formula= Test~ Type + Gender + Type*Gender, data=describeDF3,na.action=na.omit) Anova(model.lm,type='II',white.adjust='hc3')
White adjust as unequal variance.
Results came up as Type significant and Gender significant but no interaction. I used both a oneway.test ANOVA and t-test to check the Gender effect but in these tests it is coming up as not significant. Why is this?
Is it because the two way test shows whether the variable creates a reduction in the deviance of the lm and the oneway tests look at differences in means?
Any help understanding this would be great!