Thank you!! We thought it was right, it's just that the FSL FEAT User guide gives some confusing examples! e.g.
If, as well as the ANOVA test, you wanted to interpret individual contrasts: If we define m,a,b,c as the 4 PE values, then
A=a+m, B=b+m, C=c+m, D=m.
Thus the first PE, m, is level D, the second is a=A-m=A-D, etc.
To get the mean: mean = (A+B+C+D)/4 = m+(a+b+c)/4 = contrast [ 1 1/4 1/4 1/4 ]
To get A-mean: A-mean = (3a-b-c)/4 = contrast [ 0 3/4 -1/4 -1/4 ] etc.
To get D-mean: D-mean = (-a-b-c)/4 = contrast [ 0 -1/4 -1/4 -1/4 ].
Glad to know it's simpler than I thought!!
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