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From: "Laurentiu Galan" <larryg003@yahoo.com>
Newsgroups: comp.soft-sys.matlab
Subject: Very quick question about if then statements and standard deviation?
Date: Thu, 2 Dec 2010 02:13:04 +0000 (UTC)
Organization: NYU School of Medicine
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I have a matrix matrix with a bunch of returns:

How do I create a second matrix, that will calculate the standard deviations for
a trailing numbers in groups of three? i.e.  if the first two numbers will be 
0 and the nth number will be the standard deviation of the corresponding 
number in matrix 1 and the preceding 2 numbers.

I have the matrix:
matrix:                                             matrix2
-.0001                                                    0
0.003                                                     0
0.012                                               stdev of (-0.001, 0.003, 0.012)
-.002          I want matrix2:                stdev of (0.003, 0.012, -0.002     
-.2                                                   stdev of (0.012, -.002, -.2)
.                                                          .
.                                                          .
.                                                          .
0.02
-.07                                                      
0.04                                                stdev of (0.02, -0.07, 0.04)

I know it's a very trivial if then statement, but i am having some difficulty with it.

Thank you so much Matlab Forums community!