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</o:shapelayout></xml><![endif]--></head><body lang=NL link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'>Dear Nina,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'>I forgot to answer part of your question. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'>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.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'>Best,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'>Eric<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> FieldTrip discussion list [mailto:FIELDTRIP@NIC.SURFNET.NL] <b>On Behalf Of </b>Nina Kahlbrock<br><b>Sent:</b> dinsdag 23 november 2010 15:59<br><b>To:</b> FIELDTRIP@NIC.SURFNET.NL<br><b>Subject:</b> [FIELDTRIP] statistics and NaNs in single channels<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Hi all, <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>I have a question concerning statistics and missing values.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>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.).<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>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).<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>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?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Thank you in advance for any help!<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Nina<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'><o:p> </o:p></span></p><p class=formatvorlagearial10ptvor5ptnach5pt><span lang=EN-GB>- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -<o:p></o:p></span></p><p class=formatvorlagearial10ptvor5ptnach5pt><span lang=EN-GB><o:p> </o:p></span></p><p class=formatvorlagearial10ptvor5ptnach5pt><span lang=EN-GB>Nina Kahlbrock<o:p></o:p></span></p><p class=formatvorlagearial10ptvor5ptnach5pt><span lang=EN-GB>Institute of Clinical Neuroscience and Medical Psychology <o:p></o:p></span></p><p class=formatvorlagearial10ptvor5ptnach5pt><span lang=DE>Heinrich Heine University Duesseldorf<o:p></o:p></span></p><p class=formatvorlagearial10ptvor5ptnach5pt><span lang=DE>Universitaetsstr. 1<o:p></o:p></span></p><p class=formatvorlagearial10ptvor5ptnach5pt><span lang=DE>40225 Düsseldorf<o:p></o:p></span></p><p class=formatvorlagearial10ptvor5ptnach5pt><span lang=DE><o:p> </o:p></span></p><p class=formatvorlagearial10ptvor5ptnach5pt><span lang=DE>Tel.: +49 211 81 18075<o:p></o:p></span></p><p class=formatvorlagearial10ptvor5ptnach5pt><span lang=DE>Fax. .: +49 211 81 19916<o:p></o:p></span></p><p class=formatvorlagearial10ptvor5ptnach5pt><span lang=DE><o:p> </o:p></span></p><p class=formatvorlagearial10ptvor5ptnach5pt><span lang=DE>Mail: </span><span lang=FR><a href="mailto:Nina.Kahlbrock@med.uni-duesseldorf.de"><span lang=DE style='color:windowtext;text-decoration:none'>Nina.Kahlbrock@med.uni-duesseldorf.de</span></a></span><span lang=DE><o:p></o:p></span></p><p class=formatvorlagearial10ptvor5ptnach5pt><span lang=FR><a href="http://www.uniklinik-duesseldorf.de/medpsychologie"><span lang=DE style='color:windowtext;text-decoration:none'>http://www.uniklinik-duesseldorf.de/medpsychologie</span></a></span><span lang=DE><o:p></o:p></span></p><p class=MsoNormal><span lang=DE><o:p> </o:p></span></p><p>--------------------------------------------------------------------------- You are receiving this message because you are subscribed to <br>the FieldTrip list. The aim of this list is to facilitate the discussion <br>between users of the FieldTrip toolbox, to share experiences <br>and to discuss new ideas for MEG and EEG analysis. <br>See also http://listserv.surfnet.nl/archives/fieldtrip.html <br>and http://www.ru.nl/neuroimaging/fieldtrip.<br>---------------------------------------------------------------------------<o:p></o:p></p></div></body></html>
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