这个问题是关于经验的偏斜还是非参数的偏斜,还是关于估计偏斜的问题?
—
gwr
Answers:
他们使用不同的方法来计算偏斜。在帮助页面中搜索skewness()
R软件包中的内容将e1071
产生:
Joanes and Gill (1998) discuss three methods for estimating skewness:
Type 1:
g_1 = m_3 / m_2^(3/2). This is the typical definition used in many older textbooks.
Type 2:
G_1 = g_1 * sqrt(n(n-1)) / (n-2). Used in SAS and SPSS.
Type 3:
b_1 = m_3 / s^3 = g_1 ((n-1)/n)^(3/2). Used in MINITAB and BMDP.
All three skewness measures are unbiased under normality.
#Why are these numbers different?
> skewness(c(222,1122,45444), type = 2)
[1] 1.729690
> skewness(c(222,1122,45444), type = 1)
[1] 0.7061429
如果有人具有获得进一步讨论或接受教育的资格,则以下是本文引用的链接:http : //onlinelibrary.wiley.com/doi/10.1111/1467-9884.00122/abstract
e1071
软件包以澄清他在那儿的意思。如果我的帖子不清楚,则来自skewness()