<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br><div><div><br></div><div><br></div><div>On 20 Nov 2009, at 16:19, Matthew Nelson wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Thanks very much for your response. I will browse through the archive here<br>to see if I can find anything.<br><br>One source I found elsewhere on the web can be found in this book on page<br>126-127:<br><br><a href="http://www.amazon.com/reader/038720279X?_encoding=UTF8&query=126#reader_038720279X">http://www.amazon.com/reader/038720279X?_encoding=UTF8&query=126#reader_038720279X</a><br><br>If I'm understanding his description properly, this can be tested simply by<br>using the ANOVA sum of squares test statistic for an interaction while<br>permuting amongst all the conditions. I would suppose that an interaction<br>contrast could be tested similarly using the sum of squares for the contrast<br>as the test statistic while permuting amongst the combinations of conditions<br>that factor into the particular contrast. <br><br>But if you don't think that that permutation would provide the proper null<br>hypothesis for either test (the omnibus interaction or an interaction<br>contrast), I'd be curious to know.<br><br>Thanks again very much,<br><br>Matthew<br><br>On Thu, 19 Nov 2009 22:06:04 +0100, Eric Maris <e.maris@DONDERS.RU.NL> wrote:<br><br><blockquote type="cite">Dear Matthew,<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">I agree with your proposal for an interaction test in a within-sessions<br></blockquote><blockquote type="cite">design. (I have called this a within-units-of-observation design in the<br></blockquote><blockquote type="cite">Maris & Oostenveld paper.)<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">I know of no permutation test for an interaction effect in a<br></blockquote><blockquote type="cite">between-units-of-observation design. The reason is that I do not see how<br></blockquote><blockquote type="cite">such a test can be rephrased as a test of the exchangeability null<br></blockquote><blockquote type="cite">hypothesis.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">This is a recurrent question on this discussion list. You may be good to<br></blockquote><blockquote type="cite">browse through the archive of the discussion list.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Best,<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Eric<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">dr. Eric Maris<br></blockquote><blockquote type="cite">Donders Institute for Brain, Cognition and Behavior<br></blockquote><blockquote type="cite">Center for Cognition and F.C. Donders Center for Cognitive Neuroimaging<br></blockquote><blockquote type="cite">Radboud University<br></blockquote><blockquote type="cite">P.O. Box 9104<br></blockquote><blockquote type="cite">6500 HE Nijmegen<br></blockquote><blockquote type="cite">The Netherlands<br></blockquote><blockquote type="cite">T:+31 24 3612651<br></blockquote><blockquote type="cite">Mobile: 06 39584581<br></blockquote><blockquote type="cite">F:+31 24 3616066<br></blockquote><blockquote type="cite">E: e.maris@donders.ru.nl<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">MSc Cognitive Neuroscience: www.ru.nl/master/cns/<br></blockquote><blockquote type="cite"><br></blockquote><br>----------------------------------<br>The aim of this list is to facilitate the discussion between users of the FieldTrip toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis. See also http://listserv.surfnet.nl/archives/fieldtrip.html and http://www.ru.nl/neuroimaging/fieldtrip.<br></div></blockquote></div><br><div apple-content-edited="true"> <span class="Apple-style-span" style="font-size: 12px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 18px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br class="Apple-interchange-newline"><br class="khtml-block-placeholder"></div><div><br class="Apple-interchange-newline"><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">************************************************************************************</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><b style="font-weight: bold; "><span class="Apple-style-span" style="font-weight: bold; ">Guillaume A. Rousselet, Ph.D.</span></b></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><b style="font-weight: bold; "><br class="khtml-block-placeholder"></b></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial"><span class="Apple-style-span" style="font-family: Helvetica; "><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial">Lecturer</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial"><br></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial">Centre for Cognitive Neuroimaging (CCNi)</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial">Department of Psychology</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial"><div>Faculty of Information & Mathematical Sciences (FIMS)</div></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial">University of Glasgow</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial">58 Hillhead Street</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial">Glasgow, UK</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial">G12 8QB</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial"><br></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial"><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; ">The University of Glasgow, charity number SC004401</div></font></div></span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial"><br class="khtml-block-placeholder"></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><span class="Apple-style-span" style="font-family: Geneva; "><a href="http://web.me.com/rousseg/GARs_website/">http://web.me.com/rousseg/GARs_website/</a></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial"><br class="khtml-block-placeholder"></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial"><span class="Apple-style-span" style="font-family: Arial; ">Email: </span></font><a href="mailto:g.rousselet@psy.gla.ac.uk">g.rousselet@psy.gla.ac.uk</a></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial"><span class="Apple-style-span" style="font-family: Arial; ">Fax. +44 (0)141 330 4606</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><font class="Apple-style-span" face="Arial"><span class="Apple-style-span" style="font-family: Arial; ">Tel. </span></font><font class="Apple-style-span" face="Arial"><span class="Apple-style-span" style="font-family: Arial; ">+44 (0)141 330 6652</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Arial"><span class="Apple-style-span" style="font-family: Arial; ">Cell +44 (0)</span></font>791 779 7833</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><br class="khtml-block-placeholder"></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><font class="Apple-style-span" color="#0000EF"><b style="color: rgb(0, 0, 239); font-weight: bold; "><br class="khtml-block-placeholder"></b></font></div>"no test based upon a theory of probability can by itself<div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">provide any valuable evidence of the truth or falsehood</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">of a hypothesis.</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><br class="khtml-block-placeholder"></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">But we may look at the purpose of tests from another</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">viewpoint. Without hoping to know whether each separate</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">hypothesis is true or false, we may search for</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">rules to govern our behaviour with regard to them, in</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">following which we insure that, in the long run of</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">experience, we shall not often be wrong."</div><div><br class="khtml-block-placeholder"></div><div><span class="Apple-tab-span" style="white-space: pre; "><span class="Apple-style-span" style="white-space: pre; "> </span></span>Neyman J & Pearson E, 1933<div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">************************************************************************************</div><div><br class="khtml-block-placeholder"></div><div><br class="khtml-block-placeholder"></div><div><br class="khtml-block-placeholder"></div></div></div></div><br class="Apple-interchange-newline"></span><br class="Apple-interchange-newline"></div></span></div></span> </div><br></div></body></html><p>----------------------------------</p>
<p>The aim of this list is to facilitate the discussion between users of the FieldTrip toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis.</p>
<p> http://listserv.surfnet.nl/archives/fieldtrip.html</p>
<p> http://www.ru.nl/fcdonders/fieldtrip/</p>