<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'>Hi Anna,<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 style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'><div><div><p class=MsoNormal style='margin-bottom:12.0pt'>thank you for your first answer. Actually my question is really on the right way to implement a group comparison in fieldtrip (patient vs control group). <br><br>Is it ok to run an independent t-test with the following design:<br><br>design = zeros(2,n_group1+n_group2); <br>design(2,:) = 1;<br>design(1,1:n_group1) = 1:n_group1; <br>design(1,n_group1+1:end) = 1:n_group2; <br><br><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'>This is not correct. I advise you to have a look at the Fieldtrip tutorial on cluster-based permutation tests. A between-subjects experiment (e.g., patients versus controls) is formally equivalent to a between-trials experiment (explained in detail in the tutorial), and therefore should be analyzed in the same way. You can even copy-paste part of the tutorial code for the analysis of your between-subjects data.<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'>A subsequent question is whether it is possible to implement a mixed design or we always have to proceed by combining conditions and compare it between groups.<br><br><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'>I do not see the contrast between these two options. What is wrong with the second option? In fact, it is the option that is advocated in many statistics books (e.g., Maxwell & Delaney, Johnson & Wichren).<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'>Best,<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'>Eric Maris<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><br>Cheers, <br>Anna.<br><br><o:p></o:p></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm'><p class=MsoNormal><br>Message: 2<br>Date: Sat, 30 Jul 2011 20:45:12 +0200<br>From: "Eric Maris" <<a href="mailto:e.maris@donders.ru.nl">e.maris@donders.ru.nl</a>><br>To: "'Email discussion list for the FieldTrip project'"<br> <<a href="mailto:fieldtrip@donders.ru.nl">fieldtrip@donders.ru.nl</a>><br>Subject: Re: [FieldTrip] Group comparison statistics - ERF study<br>Message-ID: <03a601cc4ee8$d152b760$73f82620$@<a href="mailto:maris@donders.ru.nl">maris@donders.ru.nl</a>><br>Content-Type: text/plain; charset="us-ascii"<br><br>Hi Anna,<br><br><br><br>You can compare the two groups with respect to any linear combination that<br>can be formed using the observations in the 2 (conditions) x 2 (response<br>types) within-UO design. For testing interaction effects, these linear<br>combinations are the usual contrasts.<br><br><br><br><br><br>Best,<br><br><br><br>Eric Maris<br><br><br><br><br><br>dr. Eric Maris<br>Donders Institute for Brain, Cognition and Behavior<br><br>Radboud University<br>P.O. Box 9104<br>6500 HE Nijmegen<br>The Netherlands<br>T:<a href="tel:%2B31%2024%203612651">+31 24 3612651</a><br>Mobile: 06 39584581<br><br>F:<a href="tel:%2B31%2024%203616066">+31 24 3616066</a><br> <mailto:<a href="mailto:e.maris@donders.ru.nl">e.maris@donders.ru.nl</a>> mailto:<a href="mailto:e.maris@donders.ru.nl">e.maris@donders.ru.nl</a><br><br> <<a href="http://www.nphyscog.com/" target="_blank">http://www.nphyscog.com/</a>> <a href="http://www.nphyscog.com/" target="_blank">http://www.nphyscog.com/</a><br><br><br><br><br><br><br><br>From: <a href="mailto:fieldtrip-bounces@donders.ru.nl">fieldtrip-bounces@donders.ru.nl</a><br>[mailto:<a href="mailto:fieldtrip-bounces@donders.ru.nl">fieldtrip-bounces@donders.ru.nl</a>] On Behalf Of Anna Lambrechts<br>Sent: donderdag 28 juli 2011 11:32<br>To: <a href="mailto:fieldtrip@donders.ru.nl">fieldtrip@donders.ru.nl</a><br>Subject: [FieldTrip] Group comparison statistics - ERF study<br><br><br><br>Hi,<br><br>I am trying to run a group comparison analysis on event-related fields data<br>in a 2 (groups) x 2 (conditions) x 2 (response types) design. Is this<br>possible at all with any fieldtrip script? As far as I know implemented<br>statistics look at within-groups comparison.<br><br>Thanks,<br>Anna.<br><br>-------------- next part --------------<br>An HTML attachment was scrubbed...<br>URL: <<a href="http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20110730/1f410391/attachment-0001.html" target="_blank">http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20110730/1f410391/attachment-0001.html</a>><br><br>------------------------------<br><br>_______________________________________________<br>fieldtrip mailing list<br><a href="mailto:fieldtrip@donders.ru.nl">fieldtrip@donders.ru.nl</a><br><a href="http://mailman.science.ru.nl/mailman/listinfo/fieldtrip" target="_blank">http://mailman.science.ru.nl/mailman/listinfo/fieldtrip</a><br><br>End of fieldtrip Digest, Vol 8, Issue 40<br>****************************************<o:p></o:p></p></blockquote></div><p class=MsoNormal><o:p> </o:p></p></div></div></body></html>