MANCOVAN

Tools for Multivariate Analysis (Statistics Toolbox NOT Required)

Description

MANCOVAN provides a suite of tools for testing for group, group-group interaction, covariate, covariate-covariate interaction, and group-covariate interaction effects in the context of a multivariate response and it does so without using the Statistics Toolbox. Because MANCOVAN represents such a general model, it can be used for ANOVA, ANOVAN, ANCOVA, ANCOVAN, MANOVA, MANOVAN, and MANCOVA as well without loss of power or precision. In addition to MANCOVAN, this suite of tools includes MSTEPWISE for multivariate stepwise regression, MT for t-tests among levels of a group or for the slope of the regression line associated with a covariate, a variety of functions for creating and using custom design matrices, and plenty of examples.

• MATLAB release: MATLAB 7.7 (R2008b)

[Arnaud Messé]

Dear William,
Thanks for providing the MANCOVAN tools, it's a nice work!
In the mT function notes, you said:
"The tests may not always be the right ones in the context of either over-determined or sigma-restricted coding."
Could you argue this comment?
I have trouble to understand the canonical coding used... Because, this does not allow to compute all possible between groups comparisons. Is that correct?
Thanks in advance,

[Chris Allen]

 

[Claus Andersen]

Dear William Gruner,
Thanks for providing MANCOVA on the exchange server.
I've tried to use MANCOVA for an ANCOVA analysis, but sometimes get an error. The error occurs more frequently the more similar the two groups compared are (running Monte Carlo sim, so I impose the similarity).

The error reads:
??? Error using ==> betainc
X must be in the interval [0,1].

Error in ==> mFCDF at 44
p = betainc(a * x ./ (a * x + b), a/2, b/2);

Error in ==> mLHT at 79
p = 1 - mFCDF(G * T, q * d, D);

Error in ==> mancovan at 236
[ T(i), p(i) ] = mLHT(U, X, X0, M, M0, options);

Possibly you'd be interested in checking it out.
If need be I can also mail you the test data used.
Greetings
Claus

[William Gruner]

Thanks for the comment! I'm sure others share your concern. We've been refactoring and expanding the feature set very rapidly as our analysis tasks become more demanding, but each new release is both validated against the Matlab Statistics Toolbox and regression tested against earlier versions to make sure that the results remain correct and that the functionality remains backward-compatible. Brace yourself, because there's another update coming soon ;-) After that, I expect things to slow down markedly. Cheers!

[Mark Shore]

Just a thought that I'm certain has crossed the mind of most people looking at the update history of this submission... with nine(!) updates in 22 days, does the author consider this to be mature software ready for wider dissemination?