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Thread Subject:
multcompare

Subject: multcompare

From: J G

Date: 21 Mar, 2011 03:24:04

Message: 1 of 5

I have a small table (6x15) of data and I want to compare the 15 rows to each other to see if they are significantly different. I have tried using multcompare however I can't get this to work (I'm new to matlab). I'd be really gratefull for any help, thanks.

Subject: multcompare

From: ImageAnalyst

Date: 21 Mar, 2011 03:36:09

Message: 2 of 5

Do you have a reference row to compare against? Or do you want to see
if every one of the N rows (6 or 15???) is significantly different at
some tolerance or confidence level from the other N-1 rows? So that
you'll have N * (N-1) comparisons?

Subject: multcompare

From: ImageAnalyst

Date: 21 Mar, 2011 03:40:22

Message: 3 of 5

Assuming you have 15 rows (usually the first number, which you have as
6, is the number of rows)....

OK, rereading it does look like you'll want 15*14 comparisons. How
about if you just subtract the rows and see if the sum of the absolute
difference is greater than some value that you define as being
significantly different? How exactly do you want to define
"significant"?

Subject: multcompare

From: J G

Date: 21 Mar, 2011 04:01:04

Message: 4 of 5

Thanks for your reply. Sorry I should be more clear. Basically want to see if there is any correlation between each row. Is there a test for this?
Thanks.

ImageAnalyst <imageanalyst@mailinator.com> wrote in message <d1022d2c-b842-46a1-9644-9f89315993d1@s9g2000yqm.googlegroups.com>...
> Assuming you have 15 rows (usually the first number, which you have as
> 6, is the number of rows)....
>
> OK, rereading it does look like you'll want 15*14 comparisons. How
> about if you just subtract the rows and see if the sum of the absolute
> difference is greater than some value that you define as being
> significantly different? How exactly do you want to define
> "significant"?

Subject: multcompare

From: ImageAnalyst

Date: 21 Mar, 2011 10:24:51

Message: 5 of 5

Yes there will be a correlation. It will have some value - I don't
know what it is, or if it will be high but there will be a correlation
of some value. Look up correlation in the help for suggestions, like
corrcoeff, xcorr, xcorr2, etc..

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