R语言笔记 自定义峰度 和 偏度 函数

> mtcars<- function(x,na.omit=FALSE){

+ if(na.omit)

+ x<-x[!is.na(x)]

+ m<-mean(x)

+ n<-length(x)

+ s<-sd(x)

+ skew<-sum((x-m)^3/s^3)/n

+ kurt<-sum((x-m)^4/s^4)/n-3

+ return(c(n=n,mean=m,stdev=s,skew=skew,kurtosis=kurt))

+ }

vars<- c("mpg","hp","wt")

> sapply(mtcars[vars],mtstat)

               mpg          hp          wt

n        32.000000  32.0000000 32.00000000

mean     20.090625 146.6875000  3.21725000

stdev     6.026948  68.5628685  0.97845744

skew      0.610655   0.7260237  0.42314646

kurtosis -0.372766  -0.1355511 -0.02271075

>