<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>first compute your ERSP without removing the baseline. Second compute ersp1 = 10.^(ersp1log/10) and ersp2 = 10.^(ersp2log/10) for your two conditions, and take the average 10*log((ersp1+ersp2)/2). Let's continue this conversation off list as this might not be interesting to some users.</div><div><br></div><div>Best,</div><div><br></div><div>Arno</div><div><br><div><div>On 20 Aug 2013, at 02:33, Nikola Vukovic wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">
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<div bgcolor="#FFFFFF" text="#000000">Dear Arno,<br>
<br>
All my conditions have the same number of trials, but I'm still getting
different results using the two methods. How do I move between log and
absolute power space in command line?<br>
<br>
Best,<br>
Nikola<br>
<br>
<blockquote style="border: 0px none;" cite="mid:8FBD83D7-E24E-4A59-9FA5-C16C37E6776F@ucsd.edu" type="cite">
<div style="margin:30px 25px 10px 25px;" class="__pbConvHr"><div style="display:table;width:100%;border-top:1px solid
#EDEEF0;padding-top:5px"> <div style="display:table-cell;vertical-align:middle;padding-right:6px;"><img photoaddress="arno@ucsd.edu" photoname="Arnaud Delorme" name="compose-unknown-contact.jpg" height="25px" width="25px" id="064aeff5-edd8-4dc1-852e-966968a00da9" src="cid:part1.03020608.03020004@gmail.com"></div> <div style="display:table-cell;white-space:nowrap;vertical-align:middle;width:100%">
<a moz-do-not-send="true" href="mailto:arno@ucsd.edu" style="color:#737F92
!important;padding-right:6px;font-weight:bold;text-decoration:none
!important;">Arnaud Delorme</a></div> <div style="display:table-cell;white-space:nowrap;vertical-align:middle;">
<font color="#9FA2A5"><span style="padding-left:6px">20 August 2013
07:12</span></font></div></div></div>
<div style="color:#888888;margin-left:24px;margin-right:24px;" __pbrmquotes="true" class="__pbConvBody">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><br class="Apple-interchange-newline"></div><br></div></div>
<div style="margin:30px 25px 10px 25px;" class="__pbConvHr"><div style="display:table;width:100%;border-top:1px solid
#EDEEF0;padding-top:5px"> <div style="display:table-cell;vertical-align:middle;padding-right:6px;"><img photoaddress="vukovicnikola@gmail.com" photoname="Nikola Vukovic" name="postbox-contact.jpg" height="25px" width="25px" id="5ff0ab81-3c20-4aa8-ba77-5919d82dcd0e" src="cid:part2.04010906.00020603@gmail.com"></div> <div style="display:table-cell;white-space:nowrap;vertical-align:middle;width:100%">
<a moz-do-not-send="true" href="mailto:vukovicnikola@gmail.com" style="color:#737F92
!important;padding-right:6px;font-weight:bold;text-decoration:none
!important;">Nikola Vukovic</a></div> <div style="display:table-cell;white-space:nowrap;vertical-align:middle;">
<font color="#9FA2A5"><span style="padding-left:6px">19 August 2013
22:09</span></font></div></div></div>
<div style="color:#888888;margin-left:24px;margin-right:24px;" __pbrmquotes="true" class="__pbConvBody"><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 moz-do-not-send="true" href="http://cl.ly/image/0E010I0g1x21">http://cl.ly/image/0E010I0g1x21</a>
and <a moz-do-not-send="true" 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>
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