<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Dear Nikola,<div><br></div><div>combining conditions will concatenate the trials for the 2 conditions. So if you have the same number of trials in both conditions, the result below should be equivalent. If you have different numbers of trials, the result will differ (if you use combine, the result will be the grand average of all the trials from both conditions - this will not be the case if you average two ERSP). There are also some issues of scaling. You should not average ERSP in log space, but in absolute power space.</div><div><br></div><div>Arno</div><div><br><div><div>On 19 Aug 2013, at 14:09, Nikola Vukovic wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><div dir="ltr"><div><div><div><div>Dear list,<br><br></div>Until now, I assumed that
selecting several conditions and combining them into one condition
(using the "combine selected values" in STUDY design window) simply
averages the given conditions. Once I got more comfortable with command
line scripting, I started averaging them manually (by plotting the
conditions separately, then averaging their ersp data output. For
example ersp_avg = (ersp{1,1} + ersp{2,1})/2). However, I find that the
outputs I get when manually averaging, and when averaging variables in
STUDY design are completely different (compare <a href="http://cl.ly/image/0E010I0g1x21">http://cl.ly/image/0E010I0g1x21</a> and <a href="http://cl.ly/image/3O01242E0b0M">http://cl.ly/image/3O01242E0b0M</a>).<br>
</div>Where does this difference come from? What exactly does the "combine selected values" function do?<br><br></div>Thank you,<br></div>Nikola
</div>
_______________________________________________<br>Eeglablist page: <a href="http://sccn.ucsd.edu/eeglab/eeglabmail.html">http://sccn.ucsd.edu/eeglab/eeglabmail.html</a><br>To unsubscribe, send an empty email to <a href="mailto:eeglablist-unsubscribe@sccn.ucsd.edu">eeglablist-unsubscribe@sccn.ucsd.edu</a><br>For digest mode, send an email with the subject "set digest mime" to <a href="mailto:eeglablist-request@sccn.ucsd.edu">eeglablist-request@sccn.ucsd.edu</a></blockquote></div><br></div></body></html>