Message-ID: <EED5CBA9-AABE-4C7F-BC49-3F90D30AAD60@comcast.net>
Date: 2012-05-20T01:23:54Z
From: David Winsemius
Subject: anovas ss typeI vs typeIII
In-Reply-To: <1337468306.88083.YahooMailNeo@web130104.mail.mud.yahoo.com>
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