[R] anovas ss typeI vs typeIII

[David Winsemius]

On May 19, 2012, at 6:58 PM, jacaranda tree wrote:

> Hi all,
> I have been struggling with ANOVAs on R. I am new to R, so I created  
> a simple data frame, and I do some analyses on R just to learn R and  
> then check them on SPSS to make sure that I am doing fine. Here is  
> the problem that I've run into:
>
> when we use the aov function, it uses SS Type I as default (on SPSS  
> it is Type III). Then I used the Anova function under cars package  
> using the command:
>
> mod <- lm(DV
> ~ IV1*IV2, data = mydata,
> contrasts=list(IV1=contr.sum,
> IV2=contr.sum))
> Anova(mod, type=”3”)

Are you perhaps having a problem due to using a non-plain-text editor?  
Those quotes look "wrong".

compare " with ”

I do not think the second version of double-quote will be recognized  
correctly.


>
> Above, both of my IVs are between-SS variables. But still, results  
> from this model do not match the results from SPSS (I have to say  
> they are not too different either). But I was wondering if I am  
> doing something wrong. If what I am doing is okay, then my next  
> question is can I use the same set of commands (for Anova function)  
> if one of my IVs was within-SS and the other IV was between-SS?
>
>
> Thank you very much!
> 	[[alternative HTML version deleted]]

Part of learning R is moving away from pretty versions of formatting,

-- 

David Winsemius, MD
West Hartford, CT