How can I do the best fit of a power function with my original data

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I have two variables (x,y). we found by eye that y = x^1/2.33, but it is not perfect for what I want and also when I test the correlation it gives me ONE but I think it should not be one because there is a variance value 0.0113. I can use the 'basic fitting' but there is no option of the power function. Thanks in advance

Accepted Answer

Ameer Hamza
Ameer Hamza on 20 Jun 2018
You can use lsqcurvefit() for least square curve fitting. For example
% sample data
x = 0:10;
y = x.^0.33 + 0.2*rand(size(x));
f = @(x, xdata) xdata.^x(1); % function to fit, 'x' will be estimated
solution = lsqcurvefit(f, 0, x, y)
  3 Comments
Ameer Hamza
Ameer Hamza on 20 Jun 2018
solution is the estimated value of the exponent. you need to use (x,y) values from your own dataset.

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More Answers (1)

Torsten
Torsten on 20 Jun 2018
xdata = ...;
ydata = ...;
a0 = 1/2.33;
fun = @(a)sum((ydata-xdata.^a).*xdata.^a.*log(xdata));
a = fzero(fun,a0)
Best wishes
Torsten.

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