## Model Type III Sum of Squares [General Sta­tis­tics]

Thanks so much ElMaestro. I think I have an improved grasp of the different SS Types now thanks to you.

I also want to use the Venn Diagram when looking at the method of calculating the SSs. I am imagining a Venn Diagram with Factors A, B and C pictured as spheres that sometimes overlap.

For Type I, if I want to determine the SS for factor A first then we have SS(A). Then if the next is factor B, we have to remove the component of A in B which gives SS(B∩A'). And finally for C, we have SS(C∩A'∩B').

For Type III, we just do SS(A), SS(B) and SS(C). or something in that light. I don't know if it's the right way to imagine it.

However I want to confirm the statement that "SS results for Type I and III are the same for a balanced design". Is that true?

I read it somewhere. Though I noticed they mentioned orthogonality as well.

» Try and look at type I SS and specify subject before sequence, and sequence before subject and see what happens . Play around. Type I SS's will add up (the relative drawback is that the SS's for each factor can depend on which factors specified before others), but type III SS's won't necessarily add up.

I will definitely play around :). Thanks.

Regards,

Scopy