## Arranging data for test of statistical significance from multiple subjects

### LRBLFAST (view profile)

on 21 Apr 2013

Hi,

I have 20 different feature matrix as (NxM) from 20 different subjects. Where N (e.g. 1... 10 different features) is fixed but M varies (i.e. 1...., observations) for each subject.

How should I arrange my data such that I will know the statistical significance of each feature by including all the subject's data?

Which kind of tests are suitable when M is varying for each subject? Should I use ANOVA, MANOVA, multicompare etc. or any other?

Any help in this regard will be highly appreciated.

Thanks!

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### Tom Lane (view profile)

on 23 Apr 2013

It sounds like you have a univariate rather than multivariate problem. So anova1 rather than manova1.

You have two choices. First, put your data in the N-by-M matrix and pad with NaNs so make up the M total for each subject. Or put your data in a vector V and create a separate vector S giving the subject number for each corresponding element of V. The anova1 function will accept either form.

LRBLFAST

### LRBLFAST (view profile)

on 25 Apr 2013

Sorry for late replying, My data description is as follows: I've 10 subjects data. From each subject I've extracted 20 features (N) which were sampled over 10 seconds window,but due to variation in records for each subject the no. of samples for a feature is different (i.e. M). For e.g. the size of the feature matrix for Sub 1 = 20x217 whereas for Sub 2 = 20x245 and so on (i.e. N=fixed, M=varying). In total I have 10 such matrices, so putting them as vector (V) will be too lengthy(second choice suggested by you). The link provided in my earlier comment describes N-way repeated measures ANOVA. Will that be valid? If yes kindly suggest how to arrange?

Tom Lane

### Tom Lane (view profile)

on 25 Apr 2013

Sorry, I'm not familiar with that File Exchange program. Based on a quick look it seems to require balanced data. You might try writing to the author on the File Exchange page. He seems to respond to questions.

LRBLFAST

### LRBLFAST (view profile)

on 26 Apr 2013

Thanks very much for your time Mr. Tom Lane.

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