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Plotting Two Gaussians on One Histogram

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Michael
Michael on 17 Sep 2013
I'd like to be able to make a histogram which has two distinct gaussian curves.. like a camel with two humps on its back. Preferably creating the gaussians from randn() would be ideal.
I think the question is based on generating the gaussian and adding the index/bins to the vector/data in some way. So, if I've phrased this correctly: How do I tack on the indices to the gaussians and overlap them (and I mean like literal addition by that)?
The picture quality is kinda bad but this:
is what I'm going for. Except I'd like it to be binned like a histogram.. perhaps using bar would be more effective?? My knowledge is low in this area and I appreciate all the help you can offer!
Thanks in advance, M.A.B.

Accepted Answer

Laurent
Laurent on 17 Sep 2013
Hi,
you can create the two shifted histograms with randn.
gauss1=randn(100000,1)/2+1; %create gaussian around +1
gauss2=randn(100000,1)/2-1; %create gaussian around -1
gausssum=[gauss1;gauss2]; %combine values
The histogram can than be made with 'hist'
[N,X]=hist(gaussum,100);
plot(X,N);
Is this what you were looking for?
  1 Comment
Michael
Michael on 17 Sep 2013
Perfect! Thank you. I was trying something like this on saturday... I should review it to see where I went wrong. Thank you very much for your input!

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More Answers (1)

dpb
dpb on 17 Sep 2013
Basic idea; I've got to run so you can fill in the inbetween by adding the appropriate bin counts and drawing the line on top or however you want to do it...
a=randn(200,1); % generate a normal sample mean 0, var 1
[n1,x1]=hist(1+a*0.25); [n2,x2]=hist(0.25*a-1);
bar(x1, n1,0.4), hold on, bar(x2,n2,0.4), hold off
Adjust the multiplier on the variance as per your data...
  1 Comment
Michael
Michael on 17 Sep 2013
I also like this method. Thank you for your input as well! I appreciate your time.

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