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I used the function mix (package mixdist) to fit Gamma mixture distributions. The function gives mu and sigma parameters (output below). How can I find the scale and shape parameters ? 

Parameters: 
      pi    mu sigma 
1 0.2089 185.7 285.4 
2 0.7911 530.1 423.5
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Hint: Page 4 of the manual of the package indicates that mu represents the mean and sigma represents the standard deviation (square root of the variance):

https://cran.r-project.org/web/packages/mixdist/mixdist.pdf

Since the Gamma distribution has closed form mean and standard deviation, you can easily transformed into scale and shape:

https://en.wikipedia.org/wiki/Gamma_distribution

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    $\begingroup$ From the link about Gamma distribution, mean = scale x shape. How can I find the scale and shape values from only the mean value ? $\endgroup$ – Marine Aug 26 '16 at 13:33

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