matlab中方差、标准差、矩的函数

MATLAB中用var()计算样本方差，用标准差函数std()计算样本标准差，用矩函数moment()计算样本的各阶中心矩。

>> x=[-1 -1 1 2];
>> w=[1 2 3 4];
>> v1=var(x)


v1 =


    2.2500


>> v2=var(x,0)


v2 =


    2.2500


>> v3=var(x,1)


v3 =


    1.6875


>> v4=var(x,w)


v4 =


    1.5600


>> v5=var(x,1,w)

出错 var (line 71)
n = size(x,dim);
 
>> s1=std(x)


s1 =


    1.5000


>> s1=std(x,1)


s1 =


    1.2990


>> s1=std(x,w)


s1 =


    1.2490