Second and third sigma of standard devition.

Question

James 2014-4-21

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/126586-second-and-third-sigma-of-standard-devition

评论： Sean de Wolski 2014-4-21

Hi,

I have a big 200x1 matrix "A" and want to find the standard deviations of it. I know that the Std(x)gives you the first sigma. How do you find the second and third sigma of "A" in Matlab. I am very interested in those as whell for this data.

Thanks

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

dpb 2014-4-21

在 MATLAB Online 中打开

For what definition of "second and third sigma"? You mean the higher moments, maybe? If so and have Statistics Toolbox

doc moment

If not, compute as you would the std deviation if didn't have the function std except using the chosen moment for the power instead of 2.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Image Analyst 2014-4-21

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/126586-second-and-third-sigma-of-standard-devition#answer_134091

ComputeImageMomentsDemo.m

For what it's worth, attached here is some code to find up through the 4th central moments: mean, std, var, skewness, kurtosis. The data can be any array - doesn't need to be an image.

By the way, 200 elements is not "big", it's microscopic. Now if you had 200 million elements, then that would be big (at this point in time).