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Dear FreeSurfer experts,
I tried to examine the thickness differences between two groups after controlling for the age, gender, and mean thickness, while I got an error message below:
ERROR: matrix is ill-conditioned or badly scaled, condno = 1e+08 Possible problem with experimental design: Check for duplicate entries and/or lack of range of continuous variables within a class. If you seek help with this problem, make sure to send:
Your command line: mri_glmfit.bin --y glm/FB_demo_lh_CT/lh.FB_demo_lh_CT.thickness.10B.mgh --fsgd glm/FSGD_files/createFSGD/FB_demo_lh_CT/FB_demo_lh_CT.fsgd --C glm/FB_demo_lh_CT/PS-NP.mtx --C glm/FB_demo_lh_CT/NP-PS.mtx --surf 43kids lh --glmdir glm/FB_demo_lh_CT/lh.FB_demo_lh_CT.thickness.10B.glmdir The FSGD file (if using one) And the design matrix above Attempting to diagnose further SumSq: Min=1.258825 (col 10), Max=5.384785 (col 5) ... could not determine the cause of the problem
I have searched this problem in the mail archive. I have done the normalization for all covariables (age and mean thickness). Sex and test condition are treated as class variables. So I have no idea about the cause of the error. Here I attached the FSGD file and the matrix. The contrast is 0.5, -0.5, 0.5, -0.5, 0,0,0,0,0,0,0,0. Can someone help me? Thank you!
Best regards, Chen