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Fit a curve to a nonlinear 1D data

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Abhishek Singh
Abhishek Singh on 4 Oct 2020
Commented: Sindar on 5 Oct 2020
Hello,
I have a monthly rainfall data for a year and it is quadratic with months. I want to get the approximate equation it follows. I tried Excel and other options and the results are also okay but I was thinking if MATLAB could give a more precise equation for me. After that, I will use that equation for another variable. Below is shown the monthly data. I just want to fit a curve to it and get the equation for my further use. Thank you very much.
18.92, 21.6, 27.4, 43.07, 85.66, 230.12, 347.02, 289.74, 197.32, 95.32, 39.5, 19

Answers (1)

Sindar
Sindar on 4 Oct 2020
x=1:12;
y=[18.92, 21.6, 27.4, 43.07, 85.66, 230.12, 347.02, 289.74, 197.32, 95.32, 39.5, 19];
% fit to a quadratic (degree 2) polynomial
p = polyfit(x,y,2);
  4 Comments
Sindar
Sindar on 5 Oct 2020
what do you mean by "lesser co-efficients in p"?
Also, with only 12 data points, I'd be wary of fitting with high-order polynomials (too many parameters, likely to overfit and result in spikes between sampled points)

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