1、測試數據
a <- c(8,4,7,6,2,5)
2、最大值、最小值
> max(a) [1] 8
> min(a) [1] 2
3、平均數、中位數
> mean(a) [1] 5.333333
> median(a) [1] 5.5
4、方差、標准差
> var(a) [1] 4.666667
> sd(a) [1] 2.160247
5、相關系數、協方差
> cor(a,log(a)) [1] 0.9778993
> cov(a,log(a)) [1] 1.057501
6、NA的處理
> a <- c(8,4,7,6,2,5) > mean(a) [1] 5.333333
> a <- c(8,4,7,6,NA,2,5) > mean(a) [1] NA > mean(a,na.rm=TRUE) [1] 5.333333
> a <- c(8,4,7,6,NA,2,5) > mean(a) [1] NA > is.na(a) [1] FALSE FALSE FALSE FALSE TRUE FALSE FALSE > a[is.na(a)] [1] NA > a[is.na(a)] <- 0
> a [1] 8 4 7 6 0 2 5
> mean(a) [1] 4.571429
參考：https://www.cnblogs.com/liuchangchun/p/4456147.html