Area under distribution fit curve
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I used Statistics and Machine Learning add on to help me create a fit for my data. However, i now need to find the area under the fitted curve, and i am unable to use trapz(X,Y) since i do not have any variables and my data is a 261345x1 data set. Please advise!
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Star Strider
on 6 Sep 2021
It would help to know the function used to fit the curve (for example nlinfit).
The nonlinear curve-fitting functions require that a model function be provided in order to estimate the parameters. That function can then be used with the integral function to find the area under the fitted curve, or to calculate the fitted values to use with trapz —
t = linspace(0, 5);
s = t.^2 + randn(size(t));
fcn = @(b,x) b(1) .* x.^b(2);
B0 = rand(2,1);
B = nlinfit(t, s, fcn ,B0)
AUC1 = integral(@(x)fcn(B,x), min(t), max(t)) % Use 'integral'
AUC2 = trapz(t, fcn(B,t)) % Use 'trapz'
figure
plot(t, s, '.')
hold on
plot(t, fcn(B,t), '-r')
hold off
grid
Experiment to get different results.
.
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