statistics and NaNs in single channels

[Nina Kahlbrock]

Hi all, 

I have a question concerning statistics and missing values.

I have data of 32 subjects (divided into four groups). Between these
subjects different channels were rejected due to artifacts. I would like to
avoid interpolating those channels but continue with filling up bad channels
with NaNs (i.e. subject one has channels 1, 3, and 17 filled up with NaNs,
subject two has channels 1, 7, 19, and 33 filled up with NaNs etc.).

What I would like to look at is if there are differences between groups in
certain cortical areas (I would calculate tfrs, average over certain
channels and then run a group analysis).

Does this pose a statistical problem, as there are differing numbers of
channels contributing to the average between groups? If I do not average
over channels, would it be allowed to identify significantly different
cortical areas between groups on sensor level?

Thank you in advance for any help!

Nina

 

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - - - - - - - - - - - - - - - - - - -

 

Nina Kahlbrock

Institute of Clinical Neuroscience and Medical Psychology 

Heinrich Heine University Duesseldorf

Universitaetsstr.  1

40225  Düsseldorf

 

Tel.:      +49 211 81 18075

Fax. .:   +49 211 81 19916

 

Mail:      <mailto:Nina.Kahlbrock at med.uni-duesseldorf.de>
Nina.Kahlbrock at med.uni-duesseldorf.de

 <http://www.uniklinik-duesseldorf.de/medpsychologie>
http://www.uniklinik-duesseldorf.de/medpsychologie

 


---------------------------------------------------------------------------
You are receiving this message because you are subscribed to
the  FieldTrip list. 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.
---------------------------------------------------------------------------
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20101123/e8a30ea1/attachment.html>