Error in correlation analysis

Submitted by hoptman on

Hi,

I am trying to run a correlation analysis using the Statistical Analysis tool.   However, I'm getting the error as below.  Also, do I need to demean the data prior to doing the correlational analysis, or does DPABI do it for me?

Thanks,

Matt

    Regression Calculating...
........Undefined function 'qr' for input arguments of type 'char'.

Error in y_regress_ss (line 29)
[Q,R,perm] = qr(X,0);

Error in y_GroupAnalysis_Image (line 94)
                    [b,r,SSE,SSR, T, TF_ForContrast] = y_regress_ss(DependentVariable,[Predictor,CovVariable],Contrast,TF_Flag);

Error in y_Correlation_Image (line 71)
[b_OLS_brain, t_OLS_brain, TTest1_T, r_OLS_brain, Header] =
y_GroupAnalysis_Image(DependentVolume,Regressors,OutputName,MaskFile,CovariateVolume,Contrast,'T',0,Header);

Error in DPABI_STAT_TOOL>ComputeButton_Callback (line 503)
        y_Correlation_Image(S, SeedSeries, OutputName, MaskFile, ImageCell, TextCell);

Error in gui_mainfcn (line 96)
        feval(varargin{:});

Error in DPABI_STAT_TOOL (line 42)
    gui_mainfcn(gui_State, varargin{:});

Error in @(hObject,eventdata)DPABI_STAT_TOOL('ComputeButton_Callback',hObject,eventdata,guidata(hObject))

 
Error while evaluating uicontrol Callback

YAN Chao-Gan

Sat, 12/20/2014 - 22:49

Permalink

Hi Matt,

"Undefined function 'qr' for input arguments of type 'char'."

This error message is pretty rare, it says matlab can not found the basic command 'qr'. Did you do anything to your matlab? I will suggest you restart matlab and type in: 

which qr

to see how matlab responds.

For correlation analysis, you do not need to demean the data. 

Best,

Chao-Gan

Hi Chao-Gan,

When I do:

which qr, I get:

built-in (/var/share/MATLAB/R2012b/toolbox/matlab/matfun/@single/qr)  % single method

 

I'm using Matlab 2012b, if that matters.

 

I wonder if the error message has to do with the data type?

Undefined function 'qr' for input arguments of type 'char'.

But all the data in the file is numerical.

 

Hi Matt,

It's pretty weird that you got 'char' for X there.

What's your setting for correlation analysis? Is the Seed Series all numbers? So as covariates?

Best,

Chao-Gan

Hi Chao-Gan,

I was hoping to do a voxelwise correlation between FC for a given ROI and my variable of interest (see attached).  So, I loaded in images, but not timeseries.  Is there a way to do this with FC images?

Thanks,

Matt

Matt

Hi Matt,

You should move your variable of interest from "Text Covariates" to "Correlation Seed Series", then it should work.

Merry Christmas and Happy New Year!

Chao-Gan

Hi Chao-Gan,

That worked, thanks!  Can I do partial correlation in this manner (like FD and some other variable of interest)? 

If so, how would I set that up?  Would I use two columns or two files?  Also, how would I know which is the covariate and which is the variate of interest in the output?

Happy holidays to you as well!

Best,

Matt

Hi Matt,

Please put the variate of interest into "Correlation Seed Series".

And put all the confouding covariates into "Text Covariates". Within that text file, you can have as many columns as you want.

In this manner, you are doing partial correlation.

Best,

Chao-Gan

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