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The t-contrasts and f-contrasts meanings and interpretations can be found in any statistical textbook (Myers et al., Keppel et al.).
Briefly, A t-contrast can only be a vector, while an F-contrast can be a matrix or a vector. If the F-contrast is a vector, then its value is t^2.
The matrix can be define with integer, fractions, or decimals (if the value is define - e.g. 2/3 can not be written as a decimal). This is done to make the contrast.
I have written many previous posts on how to build contrasts.
Here is a good description of an F-test: http://mindhive.mit.edu/node/60
Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Postdoctoral Research Fellow, GRECC, Bedford VA
Research Fellow, Department of Neurology, Massachusetts General Hospital and
Harvard Medical School
Office: (773) 406-2464
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2011/8/28 yiliusan <[log in to unmask]>Hi experts,I am a SPM newbie. I need your help to understand F-contrasts in SPM8.I have done some T-contrast analysis with SPM8 before. Now I have to do some ANOVA analysis in SPM8.But I don't quite understand how to define the F-contrasts and what does it mean in different kinds of matrix (e.g. some one define matrix with integer while someone define them with fraction).I have read some related chacters in <Human brain function>, but it seems a little hard for me to get clear. I also search in this list and somewhere online trying to get some supplement reading materials to figure out what is it. However, I made little progress.So I hope you experts can make a way to help me to understand the F-contrast and recommand some effective and understandable materials to read.Thank you very much!Best!