[Eeglablist] statistical analysis problem

[cyril pernet]

Dear Anahita

May I suggest a different approach, which should solve your problem.

You can use the LIMO EEG toolbox 
(https://gforge.dcn.ed.ac.uk/gf/project/limo_eeg/) to analyse your data. 
For each participant, you build a statistical model using the markers 
for faces and objects - that gives you estimates of effects of seeing 
faces or objects and you can also compare within subject faces vs 
objects. Once this is done, you can perform e.g. a two samples T-test 
controls vs. partients on the difference (face vs object) you computed 
for each subjects. The good thing here is (1) it doesn't really matter 
that within subjects you don't have the same number of (good) trials (2) 
it doesn't matter for the T-test if you end up with different number of 
subjects (say you had to discard 2 patients because they just don't have 
any good trials at all) and (3) the analysis is performed across all 
channels and time frames so you don't have to do ad hoc selection of 
channels or time windows (note you could also select the 'best' 
electrode per subject .. have a look at our paper and tutorial)

Cyril







Subject:
[Eeglablist] statistical analysis problem
From:
anahita khorrami <asaliam20 at gmail.com>
Date:
15/08/2012 05:18

To:
eeglablist at sccn.ucsd.edu


Hello EEG experts
I have some questions about statistical analysis. I had two groups with 
18 participants in each of them. on of the groups is typical 
participants and the other one person with disorder. they examine face 
comparing with other objects . finally P7 and P8 analyzed for face. in 
group with disorder most of channels have value for latency and 
amplitude but in other group 50% of person had zero. now zero here is 
value or miss data what should I do here because the mean of latency get 
less than 100 ms. I had chose the channels which are popular for face 
processing and the window was 130 t0 200 ms. what should I do know. I 
would appreciate answer me.
best regards
Anahita Khorrami




-- 
Dr Cyril Pernet,

Academic Fellow
Brain Research Imaging Center
http://www.bric.ed.ac.uk/
Division of Clinical Neurosciences
University of Edinburgh
Western General Hospital
Crewe Road
Edinburgh
EH4 2XU
Scotland, UK

cyril.pernet at ed.ac.uk
tel: +44(0)1315373661
http://www.sbirc.ed.ac.uk/LCL/
http://www.sbirc.ed.ac.uk/cyril

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