[R] Trouble phrasing an R command that will run the model i need (ANOVA, nes
dalelemu at hotmail.com
Sat Mar 25 03:41:46 CET 2006
Thank-you very much for replying, - in answer to your questions:
*"As I understand what you wrote, all factors but linelabel are crossed,
with linelabel nested within all the other factors?"
That's exactly it,
*" What is in the highest order cells? Single observations, or multiple
I would say "single observations" - but i have to confess I'm not entirely
sure what you mean by "multiple scores".
Any one data point refers to a single animal (an individual fly, to be
exact) giving a single value for a response variable, and having a single
state with respect to each factor. One of my datasets involves crosses
rather than flies, but it's the same set-up for them: each individual cross
only gives one value for a response variable, and has one state with respect
to each factor.
Just in the interests of clarifying things as much as possible: one of my
datasets looks like this(apologies if the formatting gets weird):
foresttype region crosstype experiment linelabel yproductivity
l g wx 1 al1
l g wx 1 al2
... and so on.
Each horizontal line refers to a single observation. The first horizontal
line, for example, refers to a single cross that was found to have a
yproductivity value of "63", and that cross happened to be in the "l"
foresttype, the "g" region, it was crosstype "wx", in experiment "1", and of
linelabel "al1". And any one cross only appears once in the dataset, so each
horizontal line refers to a distinct cross, about which a single observation
has been made.
Is that the kind of information you were looking for?
>From: John Vokey <vokey at uleth.ca>
>To: dalelemu at hotmail.com
>Subject: RE: [R] Trouble phrasing an R command that will run the model i
> need (ANOVA, nested)
>Date: Fri, 24 Mar 2006 09:41:49 -0700
> I could probably help you with aov(), but I need more information about
>your design. As I understand what you wrote, all factors but linelabel
>are crossed, with linelabel nested within all the other factors? What is
>in the highest order cells? Single observations, or multiple scores?
> BTW, Anova() has no methods for the output from aov(), you need to use
>summary(aov()); hence, the type III SS of Anova() aren't directly
>available for aov(). But, you wouldn't want them anyway, because they
>aren't the type III SS you probably were expecting (e.g., such as those
>found in SAS or SuperAnova).
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