> 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
>
原文地址：http://jackwxh.blog.51cto.com/2850597/1761180
