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,

1. Intercept (all '1')

2. time (from baseline time point)

3. time2

4. Patients group = 1, Control = 0

5. 4.X time

6. 4.X time2

7. Patients group = 0, Control = 1

8. 7. X time

9. 8. X time2

10. age

11. extra values for covariate

1.

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?

2.

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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