How may I show a mixture distribution?

I truly appreciate if someone answers how to show a mixture distribution? My data ia attached and I know this data is not enough to claim a multimodal distribution confidently. Assuming enough data points, how I can show a multimodal dataset? I means I want to show a data set like the attached figure (the figure is not mine and I only use it to express my question). Thank you in advance!

[roberto rocchetta]

Hi,

you can try to test unimodality with the Komogorov-Smirnov test.

If Xdata=A is your data:

Xnorm=(Xdata-mean(Xdata))/std(Xdata); % standard scale

r=kstest(Xnorm)

help kstest

[Maria Amr]

roberto rocchetta, Thank you so much for your help!

Answer 1

[Jeff Miller]

Here is an example of plotting a mixture that produces a graph similar to yours example:

pd1 = makedist('normal',1,1);  % probability distribution 1 is normal with mu=1, sigma=1
pd2 = makedist('normal',4,1.5);  % probability distribution 2 is normal with mu=4, sigma=1.5
prob2 = 0.25;  % 25% of the data comes from pd2

xrange = -2:0.01:10;  % some sample x values at which to compute pdfs

pd1pdf = pd1.pdf(xrange) * (1 - prob2);
pd2pdf = pd2.pdf(xrange) * prob2;

mixpdf = pd1pdf + pd2pdf;

plot(xrange,pd1pdf);
hold on
plot(xrange,pd2pdf);
plot(xrange,mixpdf);
legend('Component1','Component 2','mixture');

Hope that helps...

[Maria Amr]

Jeff Miller, Really appreciated! It is working very well. Big like!

[Jeff Miller]

:)