statistics and NaNs in single channels

[Eric Maris]

Dear Nina,

 

 

I forgot to answer part of your question. 

 

The presence of NaNs in your data does not pose any statistical problem. The
only relevant issue is whether our code can deal with the NaN-structure in
your data.

 

Best,

 

Eric

 

 

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

 

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

 

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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