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Subject: Re: Estimation of variables to minimize the sum of residuals
Date: Tue, 6 Nov 2012 03:21:09 +0000 (UTC)
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"Prakhar " <prakhar_cool@yahoo.com> wrote in message <k79nrs$oss$1@newscl01ah.mathworks.com>...
> res = x - f  
> (e.g.: res(1) = x(1) - (a + b*y(1) + c*y(1)^2).
> Define sum of square of residuals as: 
> s = sum(res.^2). 
> Now, i need to find variables a, b, c in such a way so that the sum of residuals 's' is minimum. 
- - - - - - - - -
  This is a simple problem in linear regression.  We assume x and y are column vectors as shown.  Do:

 abc = [ones(size(y)),y,y.^2]\x;

where 'abc' will be a three-element column vector containing the optimum a, b, and c coefficients in that order.

Roger Stafford