statistics and NaNs in single channels

[Eric Maris]

Dear Nina,

 

 

I would say, give it a try. When I programmed it (together with Robert
Oostenveld), the objective was to make all functions NaN-aware. I also
remember some successful tests. However, as far as I know, not many people
rely on the “NaN-awareness” of our code. So, I’m curious what will happen.

 

Best,

 

 

dr. Eric Maris
Donders Institute for Brain, Cognition and Behavior

Radboud University
P.O. Box 9104
6500 HE Nijmegen
The Netherlands
T:+31 24 3612651
Mobile: 06 39584581

F:+31 24 3616066
mailto:e.maris at donders.ru.nl

http://www.nphyscog.com/

 

 

 

 

 

 

From: FieldTrip discussion list [mailto:FIELDTRIP at NIC.SURFNET.NL] On Behalf
Of Nina Kahlbrock
Sent: dinsdag 23 november 2010 15:59
To: FIELDTRIP at NIC.SURFNET.NL
Subject: [FIELDTRIP] statistics and NaNs in single channels

 

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

 

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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

 

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