[R] Type III Sum of Squares Calculation

[John Fox]

Dear Karth,

The Anova function in the car package can calculate "type-III" sums of 
squares, though it doesn't do so by default. Be careful with the contrast 
coding or you will get nonsense (and you might want to think about whether 
you really want type-III SSs).

I hope that this helps,
  John

At 08:01 AM 10/21/2003 -0400, Subramanian Karthikeyan wrote:
>HI All:
>
>Can anyone give me the formulae/steps for calculating the type III sum of
>squares for an unbalanced 2-way ANOVA design?  Eg. we are looking at 8
>treatments x 4 doses, with unequal numbers of replications within the
>groups.  I really need the stepwise calculation, as I would try to put it
>in my own code (possibly in Visual Basic) to automate the task.

-----------------------------------------------------
John Fox
Department of Sociology
McMaster University
Hamilton, Ontario, Canada L8S 4M4
email: jfox at mcmaster.ca
phone: 905-525-9140x23604
web: www.socsci.mcmaster.ca/jfox