MATLAB: How to plot exponential pdf over a distributed data

best fit distributionexponential distributionexppdfplot a model

in order to find the best fit model
I want to produce this figure (a data & best fit over it):
so I try:
 v=1:25;
n=[10;7;6;21;14;18;23;33;28;31;34;30;32;48;43;46;39;47;40;45;51;47;45;45;23];
plot(v,n,'*b')
ex=expfit(n);
E=exppdf(n,ex);
hold on
plot(v,E,'-r')
but it produce this figure:
how to modify the code to get the first figure?

Best Answer

Fourteen hours ago I was asleep here in GMT-7 land.
I believe you are mistaking the exponential distribution for the exponential function.
This produces a good fit to your data:
v=1:25;
n=[10;7;6;21;14;18;23;33;28;31;34;30;32;48;43;46;39;47;40;45;51;47;45;45;23];
plot(v,n,'bp')
expfcn = @(b,x) b(1) + b(2).*exp(b(3).*x);              % Three-Parameter Exponential Function
B0 = [50; -50; -0.5];                                   % Initial Parameter Estimates
B = nlinfit(v(:), n(:), expfcn, B0);                    % Estimate Parameters
E = expfcn(B,v);                                        % Simulate Function
hold on
plot(v,E,'-r')
I used the nlinfit function because I know you have the Statistics Toolbox.
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