Could someone explain me this. So I have a column that I want to use as a regressor in my TBSS analysis. I created a matrix without demeaning this value and I got a significant value at p<0.05 of what I expected. Then I demeaned the regressor and also I used the -D option and after 5000 permutations no significance was found in any direction. Why? If someone could help guide me in the right direction, I would greatly appreciate it.
Thanks in advance.
Rodrigo
My non-demeanded design and contrast matrix are (I used this same matrix when using the -D option):
design.mat (sex and age as covariates):
/Matrix
Sex Age Regressor Variable
1.000000e+00 7.500000e+01 1.634750e+03
0.000000e+00 7.500000e+01 1.153250e+03
0.000000e+00 8.300000e+01 3.151000e+03
0.000000e+00 7.300000e+01 1.651000e+03
0.000000e+00 8.100000e+01 1.503250e+03
1.000000e+00 7.100000e+01 1.325500e+03
.
.
.
design.con:
/Matrix
0.000000e+00 0.000000e+00 1.000000e+00
0.000000e+00 0.000000e+00 -1.000000e+00
My demeaned design matrix and contrast are:
design.mat (sex and age as covariates):
/Matrix
Age Sex Regressor
1.000000e+00 7.500000e+01 -6.570900e+02
0.000000e+00 7.500000e+01 -1.138590e+03
0.000000e+00 8.300000e+01 8.591600e+02
0.000000e+00 7.300000e+01 -6.408400e+02
0.000000e+00 8.100000e+01 -7.885900e+02
1.000000e+00 7.100000e+01 -9.663400e+02
.
.
.
'
design.con:
/Matrix
0.000000e+00 0.000000e+00 1.000000e+00
0.000000e+00 0.000000e+00 -1.000000e+00
|