I've run a factorial ANOVA investigating the effects of depth and breakage on length but also including species as a factor for control. It's given me 1 for the degrees of freedom and I don't understand how to find the 'within' and 'between' degrees of freedom. Can I work these out manually from the variables I've put in? (Would be a lot easier than trying to go back into R).
Here's the code I used:
> model<-lm(Length~Breakage+Depth+Species,data=pond2) > Anova(model,type="II") Anova Table (Type II tests) Response: Length Sum Sq Df F value Pr(>F) Breakage 5134 1 21.9780 5.097e-06 *** Depth 3 1 0.0112 0.916 Species 27273 1 116.7572 < 2.2e-16 *** Residuals 46718 200 ---
We were looking at shells - there were 204 shells in total. Each shell was categorised as broken - yes or no - and by depth - buried or surface. There were 2 different species. No interaction terms were included (a lot of the explanations I've been looking at include interaction dfs - I don't know whether this applies with no interaction terms in the model?).
What df should I quote in my results? So far my best guess is 3 (the sum of the factors' df) and 201 (the total sample size minus the sum of the factors' df).
Thank you very much for any help!