Dear Martin Reuter,
Thank you for your reply.
Our patients have several time points, but controls have only 1 time points, so when I coded the patients group =1, controls groups = 0 , the 2. time and 3. time2 column were same as 5. 4.X time 6. 4.X time2 column. and 8. 7. X time and 9. 8. X time2 were all zeros.
And then, how about this X matrix (Subjects N X 5)?
1. Intercept (all '1') 2. 4.X time (from baseline time point) 3. 4.X time2 4. age 5. extra values for covariate
is it a vallid matrix for test the effects of group X time2 ?
Thank you,
Han.
On Sat, May 21, 2016 at 3:13 PM, Martin Reuter mreuter@nmr.mgh.harvard.edu wrote:
Hi Han, Try to find a local statistician to help you with your analysis. About your matrix: rows need to be number of all time points from all subject. Time 2 should probably not be there. Also columns 7-9 need to be dropped (they are just the negative of the rows before).
Best Martin On May 21, 2016 3:32 PM, Hanbyul Cho hanbyul.h.cho@gmail.com wrote:
Dear FreeSurfer Team,
I processed in MATLAB for Linear Mixed Effects Models Analysis with this X matrix:
X matrix is 'Subjects N X 11', 11 columns are as follow,
Intercept (all '1')
time (from baseline time point)
time2
Patients group = 1, Control = 0
4.X time
4.X time2
Patients group = 0, Control = 1
- X time
- X time2
age
extra values for covariate
When I process this command, [lhTh01,lhRe01] = lme_mass_fit_EMinit(X,[1],Y,ni,lhcortex,3,4) The MATLAB windows print the warning alarm repeatedly. " Warning: Matrix is close to singular or badly scaled. Results may be inaccurate." Is this X matrix something wrong?
After complete 'lme_mass_fit_EMinit' process with the warning, I tried the next command, [lhRgs01,lhRgMeans01] = lme_mass_RgGrow(lhsphere, lhRe01, lhTh01,lhcortex,2,95); This command took a long time to process, and it caused the whole stop MATLAB works. Is it also because of the X matrix...?
Could you let me know the solution for the X matrix problems ?
Best Wishes,
Han
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