函数定义和控制流
1.编写函数
cal_T <- function(x,y){
m <- length(x);n <- length(y)
S <- ( (m-1) * var(x) + (n-1) * var(y)) / (m+n-2)
T <- (mean(x) - mean(y)) / ( sqrt(S *( 1/m + 1/n)) )
list(两样本的T统计量=T)
}
> A <- c(64,45,65,78,54,49,87,56,86,84,75,64,85,94,63,84,64)
> B <- c(53,45,75,65,34,76,45,64,65,75)
> source('~/Documents/R /cal_T.R')
> cal_T(A,B)
$两样本的T统计量
[1] 1.817069
>
>
2.控制流
>
> if(expr1){
> expr2
> }else{
> expr3
> }
>
> if(3>2){print(T)}
[1] TRUE
>
> > x <- 3
> y <- 2
> if(x<=y){
+ print(x)
+ }else{
+ print(y)
+ }
[1] 2
>
>
> for(var in vector){
> expr
> }
>
> for(i in 1:3){print(i)}
[1] 1
[1] 2
[1] 3
>