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<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>Hi all, <o:p></o:p></span></font></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>I have a question concerning statistics and missing
values.<o:p></o:p></span></font></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>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></font></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>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></font></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>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></font></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>Thank you in advance for any help!<o:p></o:p></span></font></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>Nina<o:p></o:p></span></font></p>

<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>

<p class=FormatvorlageArial10ptVor5ptNach5pt><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt'>- - - - - - - - - - - - - - - - - - - - - -
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -<o:p></o:p></span></font></p>

<p class=FormatvorlageArial10ptVor5ptNach5pt><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt'><o:p> </o:p></span></font></p>

<p class=FormatvorlageArial10ptVor5ptNach5pt><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt'>Nina Kahlbrock<o:p></o:p></span></font></p>

<p class=FormatvorlageArial10ptVor5ptNach5pt><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt'>Institute of Clinical Neuroscience and
Medical Psychology <o:p></o:p></span></font></p>

<p class=FormatvorlageArial10ptVor5ptNach5pt><font size=2 face=Arial><span
style='font-size:10.0pt'>Heinrich Heine University Duesseldorf<o:p></o:p></span></font></p>

<p class=FormatvorlageArial10ptVor5ptNach5pt><font size=2 face=Arial><span
style='font-size:10.0pt'>Universitaetsstr.  1<o:p></o:p></span></font></p>

<p class=FormatvorlageArial10ptVor5ptNach5pt><font size=2 face=Arial><span
style='font-size:10.0pt'>40225  Düsseldorf<o:p></o:p></span></font></p>

<p class=FormatvorlageArial10ptVor5ptNach5pt><font size=2 face=Arial><span
style='font-size:10.0pt'><o:p> </o:p></span></font></p>

<p class=FormatvorlageArial10ptVor5ptNach5pt><font size=2 face=Arial><span
style='font-size:10.0pt'>Tel.:      +49 211 81 18075<o:p></o:p></span></font></p>

<p class=FormatvorlageArial10ptVor5ptNach5pt><font size=2 face=Arial><span
style='font-size:10.0pt'>Fax. .:   +49 211 81 19916<o:p></o:p></span></font></p>

<p class=FormatvorlageArial10ptVor5ptNach5pt><font size=2 face=Arial><span
style='font-size:10.0pt'><o:p> </o:p></span></font></p>

<p class=FormatvorlageArial10ptVor5ptNach5pt><font size=2 face=Arial><span
style='font-size:10.0pt'>Mail:     </span></font><span lang=FR><a
href="mailto:Nina.Kahlbrock@med.uni-duesseldorf.de"><font color=black><span
lang=DE style='color:windowtext;text-decoration:none'>Nina.Kahlbrock@med.uni-duesseldorf.de</span></font></a></span><o:p></o:p></p>

<p class=FormatvorlageArial10ptVor5ptNach5pt><font size=2 face=Arial><span
lang=FR style='font-size:10.0pt'><a
href="http://www.uniklinik-duesseldorf.de/medpsychologie"><font color=black><span
lang=DE style='color:windowtext;text-decoration:none'>http://www.uniklinik-duesseldorf.de/medpsychologie</span></font></a></span><o:p></o:p></font></p>

<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>

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