<div dir="ltr">Hi <span style="font-family:arial,sans-serif;font-size:13px">George,</span><div><span style="font-family:arial,sans-serif;font-size:13px"><br></span></div><div style><font face="arial, sans-serif">You are right, getting logarithm of the trials and then average is equivalent to the multiplying trials and then getting log. It remains that whether summing or multiplying trials can reduce the outliers.</font></div>
<div style><font face="arial, sans-serif"><br></font></div><div style><font face="arial, sans-serif">I therefore really doubt this way of analysis can remove or suppress the outliers.</font></div><div style><font face="arial, sans-serif"><br>
</font></div><div style><font face="arial, sans-serif">Thanks</font></div><div style><span style="font-family:arial,sans-serif"> </span><br></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">
On 9 March 2013 14:34, George Wallis <span dir="ltr"><<a href="mailto:wallisgj@gmail.com" target="_blank">wallisgj@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Dear fieldtrip experts<br>
<br>
When computing condition averages of TF transformed data, I take the log of the trialwise data before averaging over the trials for a given condition. As I was taking the log of the trialwise data for trialwise analyses, this seemed the most consistent approach. However, I notice it isn't implemented in fieldtrip (it requires a tweak of the ft_freqanalysis function), and the tf averages tend to look noisier this way than if they are averaged before taking the log.<br>
<br>
Does anyone have any insight into whether this is a sensible way to generate condition averages? I originally thought this would reduce the influence of outlier trials - but since it is equivalent to taking the log of the product of all the trials within a condition, perhaps it is going to do the opposite?<br>
<br>
George<br>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br>Hamid R. Mohseni, PhD<br>Post-Doctoral Research Assistant<br>Institute of Biomedical Engineering<br>University of Oxford, OX3 7DQ, UK<br>Tel: +44 (0) 1865 2 83826<br>
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