How to determine the parameters of statistical distributions

5 次查看（过去 30 天）
vedesh Mohit
vedesh Mohit 2018-3-26
评论： Star Strider 2018-3-26
Hey, I have a dataset which consist of hourly wind speed points. I would like to know ho to use the "mle" command to determine the estimates for the parameters of a weibull, rayleigh, gamma and chi-square distribution?

请先登录，再回答此问题。

采纳的回答

Star Strider
Star Strider 2018-3-26
Use the Statistics and Machine Learning Toolbox fitdist (link) function.
  5 个评论
显示 3更早的评论
vedesh Mohit
vedesh Mohit 2018-3-26
Yea I know fitdist is not an app, I was just testing out the distribution fitter app because it has these distributions built in already. However I think the issue that I am facing is that even if I use the app or the fitdist function, my wind speed data consist of points with the value 0 and these distribution does not consider zero to be a positive integer. Is there a way I could go about doing this? If I exclude the zeros, would that be considering as biasing the results?
Star Strider
Star Strider 2018-3-26
I usually substitute a very small scalar for zero entries, usually 1E-7, 1E-8 (essentially sqrt(eps)) or something in that range. I choose the magnitude so that squaring it remains a very small scalar, rather than zero, since zero could result in non-finite results. That also does not (in my experience at least) significantly affect the estimated distribution parameters.
However it could affect the parameter values if the rest of your data have very small amplitudes as well. The only solution for that might be to do your calculations in the Symbolic Math Toolbox, where extended precision is allowed. Then you could use an even smaller symbolic scalar to substitute for zero values.

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Half-Normal Distribution 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by