Get the mean and standard deviation of the lower half of the first mode of a bimodal distribution

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Hi, I have a bimodal distribution (in the form of a vector) from which I want to fit a gaussian distribution to the lower half of the first mode and calculate the mean and standard deviation of that distribution.
Any advice?

Accepted Answer

Image Analyst
Image Analyst on 4 Sep 2020
Here is code that uses fitnlm() to fit two Gaussians, and one that fits multiple Gaussians.
  2 Comments
Image Analyst
Image Analyst on 6 Sep 2020
Stephen, add these lines:
Excel.ActiveWorkbook.Save;
Excel.Quit;
delete(Excel);
clear('Excel')
See attached utilities for Excel.

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More Answers (1)

Abdolkarim Mohammadi
Abdolkarim Mohammadi on 2 Sep 2020
Edited: Abdolkarim Mohammadi on 2 Sep 2020
You can first determine the elements that are in the lower half
LowerHalfMask = Data <= mean(Data);
Then calculate the statistics
LowerHalfMean = mean(Data(LowerHalfMask));
LowerHalfStd = std(Data(LowerHalfMask));
To fit a distribution, you can first collect the elements of the lower half
LowerHalfValues = Data(LowerHalfMask);
Then use the Curve Fitting App (type cftool in the command window).
  1 Comment
Audun Kvalvaag
Audun Kvalvaag on 4 Sep 2020
Thanks, I solved it by mirroring the lower half of the first mode with the flip function. I could then use this gaussian fit function: https://www.mathworks.com/matlabcentral/fileexchange/35122-gaussian-fit to get the mean and standard deviation.

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