<div dir="ltr">Dear Stephen and Steve, <div><br></div><div>Thank you for your answers. </div><div><br></div><div>Stephen, if I understand you correctly, option 1 means I have to compute the grand average again (using ft_timelockgrandaverage), which is what I tried to avoid. </div>
<div><br></div><div>I tried option 2 though, and it didn't work. </div><div>When I used a zero entry at the uvar line, the data stayed exactly the same (as if the subject was not excluded). When I used a zero entry at the ivar line (or at both lines), i get an error message saying "invalid specification for the design array".</div>
<div><br></div><div>I also tried skipping the entry all together, but got an error message saying "the size of the design matrix does not match the number of observations in the data" </div><div><br></div><div>
An I doing something wrong? </div><div><br></div><div>Steve, I guess I can do that.. the reason I'm asking is cause I want to "play" with the data a bit - remove a different subjects each time and see if I still get the same pattern. So I thought it would be easier if I did not have to compute the grand average again and again. </div>
<div><br></div><div>Thanks!</div><div>Roni</div><div><br><div class="gmail_quote">
On 10 May 2012 14:07, Stephen Whitmarsh <span dir="ltr"><<a href="mailto:stephen.whitmarsh@gmail.com" target="_blank">stephen.whitmarsh@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi Tony,<br>
<br>
Thanks for your question.<br>
<br>
First of all, I do not fully understand what you mean with 'without<br>
computing the averages again', but I'll have a shot at it.<br>
<br>
In ft_freq/timelock-statistics you enter all your 'units of<br>
observations', i.e. data structures per subject or condition that you<br>
want to compare, together with the design matrix. The designmatrix is<br>
a one or two row matrix with as many columns as your have<br>
data-entries. One of the rows codes the group/condition membership of<br>
those entries (the independent variable). They can be subjects (group<br>
analysis) or trials (within-subjects analysis). Another row might be<br>
used to code the observation number in case you are doing a paired<br>
test.<br>
<br>
To exclude one data entry (i.e. subject) for your<br>
ft_timelockstatistics you could either:<br>
1) not enter that datastructure as data in ft_freqstatistics, and also<br>
remove it from your design matrix.<br>
2) keep your input to ft_timelockstatistics the same but use a zero<br>
for that entry in you design matrix. In this case that data input will<br>
not be used to calculate your statistics.<br>
<br>
I would say the second option is more elegant, but it is more prone to<br>
mistakes perhaps. You would do me a favour if you would doublecheck<br>
that it gives you the same results as option 1.<br>
<br>
I hope this answers your question,<br>
<br>
Stephen<br>
<div><div><br>
<br>
<br>
On 10 May 2012 12:09, Roni Tibon <<a href="mailto:ronitibon@gmail.com" target="_blank">ronitibon@gmail.com</a>> wrote:<br>
> Hi all,<br>
> Is there an elegant way to exclude a subject from the statistical analysis<br>
> when using ft_timelockstatistics, without computing the averages again while<br>
> excluding the subject?<br>
><br>
> Thanks!<br>
> Roni<br>
><br>
> --<br>
> /\.../\<br>
> ( -- ---)__{}<br>
> (_.._...._)<br>
><br>
> <a href="http://shkafkafim.blogspot.com/" target="_blank">http://shkafkafim.blogspot.com/</a><br>
><br>
><br>
</div></div>> _______________________________________________<br>
> fieldtrip mailing list<br>
> <a href="mailto:fieldtrip@donders.ru.nl" target="_blank">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>
_______________________________________________<br>
fieldtrip mailing list<br>
<a href="mailto:fieldtrip@donders.ru.nl" target="_blank">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>
</blockquote></div><br><br clear="all"><div><br></div>-- <br><div dir="ltr"> /\.../\<br> ( -- ---)__{}<br> (_.._...._)<br><br><a href="http://shkafkafim.blogspot.com/" target="_blank">http://shkafkafim.blogspot.com/</a><br>
</div><br>
</div></div>