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Thread: "Naturally occurring" left-skewed distributions?

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    "Naturally occurring" left-skewed distributions?




    hello there. for thesis purposes i'm finding myself with the need to simulate left-skewed distributions with a level of skewness i can determine through the parameters that define the distribution... so i can't really work with flipping around the distribution through transformations (e.g. multipliying a chi-square distirbution times -1).

    up to now i'm only aware of the beta distribution, so that if in R type something like

    Code: 
    rbeta(1000, shape1=5, shape2=1)
    i get the left-skew i'm looking for.

    i'm just curious whether anyone else out there is aware of another family of distributions which, like the beta, can change their skwness depending on their parameters. i thought there were more out there, but after checking a few potential candidates (chi-squre, log-normal, gamma, exponential, etc...) i can see that they're all right skewed...

    thanks!
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    Re: "Naturally occurring" left-skewed distributions?

    Maybe the power exponential family could be of use. Look at version 2 at the wikipedia.

    The R package “normalp” could maybe be useful. Search for “A Software Tool for the Exponential Power Distribution: The normalp package”)

    Otherwise the gamlss package has got a lot of distributions including estimation of skewed distributions. Se www.gamlss.org

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    Re: "Naturally occurring" left-skewed distributions?


    I don't have emotions and sometimes that makes me very sad.

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