[R] ANOVA of a sort

[Joris Meys]

This is a typical problem we give as a homework to students. If you
can't solve this yourself, you really need to brush up your
statistical knowledge or look for a statistician close by to cooperate
with.

Take a look at these :

http://www.ats.ucla.edu/stat/r/seminars/repeated_measures/repeated_measures.htm
http://gribblelab.org/2009/03/09/repeated-measures-anova-using-r/
http://www.r-statistics.com/2010/04/repeated-measures-anova-with-r-tutorials/

If you read through the documentation, you should get a fair idea of
whether or not your data is suited to use a repeated measures anova,
and if so, how you'd have to specify your model in R.

Good luck with it.
Cheers
Joris

On Thu, Jun 10, 2010 at 1:17 AM, Claus O'Rourke <claus.orourke at gmail.com> wrote:
> Dear R Help,
>
> I have a general question - I know this is the R list, but I hope
> someone can help me out a little as I've always found the help here to
> be absolutely fantastic.
>
> I have run a psychological study where participants are given multiple
> stimuli and their responses to those stimuli are measured on the same
> numerical scale, i.e., the data is something like
>
> Participant Stimulus Measurement
>  p1                 s`1            5
>  p1                 s`2            6.1
>  p1                 s`3            7
>  p2                 s`1            4.8
>  p2                 s`2            6
>  p2                 s`3            6.5
>  p3                 s`1            4
>  p3                 s`2            7
>  p3                 s`3            6
>
> I would like to be able to measure the between participant variability
> for my data - i.e., determine whether measurements are relatively
> homogeneous across participants and whether there are very strange
> outliers (i.e., participants who maybe gave random or purposefully
> incorrect answers).
>
> Can anyone point me towards the correct type of tests for quantifying
> this?  I have read that a repeated measure ANOVA might be a starting
> point.
>
> Many many thanks for any help you can give me!
>
> Claus
>
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Joris Meys
Statistical consultant

Ghent University
Faculty of Bioscience Engineering
Department of Applied mathematics, biometrics and process control

tel : +32 9 264 59 87
Joris.Meys at Ugent.be
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