depsamplesF

Nadia Müller nadia.mueller at UNI-KONSTANZ.DE
Wed Sep 9 16:43:08 CEST 2009


Hi Eric and Stephan,

thanks a lot for testing and implementing that stuff!!
And also for the background information. It's much clearer now why we
have the scaledstat and how the test statistic is calculated.

Best,
Nadia

Am 09.09.2009 um 13:57 schrieb Stephan Moratti:

> Hi Eric y Nadia,
>
> Ok, I have made a test of depsamplesF comparing results of
> depsamplesF and
> SPSS. I get the same results. I used data from an experiment and
> chose a
> timepoint and one channel that were indicated to be significant by
> dempsamplesF. In the attached TEST_dempsamplesF.mat file it is
> "testmat"
> (24 subjects 3 conditions). The variable "dat" is the reshaped
> "testmat". The
> structure "s" contains the results of depsamplesF. I added the
> variable
> scaledstat as the field "F" to "s" as it is the F value. The attached
> file "SPSSoutput.bmg" is a screen shot of the SPSS output entering
> testmat in
> a MANOVA. The results  are the same:
> F(2, 22) = 6.627, p = 0.006
>
> We can also calculate Wilk's lambda from T^2 (see page 232 formula
> 5-13 of
> the Johnson 1998 edition) as:
>
> lambda = 1/(1 + s.stat/(24-1));
>
> and get 0.624, the same as in SPSS. Maybe, as people are more used
> to F
> values, it would be useful to have the F(scaledstat)  value also in
> the "s"
> structure (and later after using timelockstats or freqstats to have
> a matrix
> containing the F values besides the T^2 values).
>
> Thanks for implementing that great stuff in fieldtrip and making it
> accessible
> for all users !
>
> Best,
>
> Stephan
>
>
> ----------------------------------
> The aim of this list is to facilitate the discussion between users
> of the FieldTrip  toolbox, to share experiences and to discuss new
> ideas for MEG and EEG analysis. See also http://listserv.surfnet.nl/archives/fieldtrip.html
>  and http://www.ru.nl/neuroimaging/fieldtrip.
> <SPSSoutput.bmp><TEST_dempsamplesF.mat>

----------------------------------
The aim of this list is to facilitate the discussion between users of the FieldTrip  toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis. See also http://listserv.surfnet.nl/archives/fieldtrip.html and http://www.ru.nl/neuroimaging/fieldtrip.



More information about the fieldtrip mailing list