AST 232 lecture 02

class work

x=c(5,10,2,6,3,8,7)
mean(x)

## [1] 5.857143

sd(x)

## [1] 2.794553

mu <- mean(x)
mu

## [1] 5.857143

Extra

x=c(5,10,2,6,3,8,7)
for (i in 1:6)
{
  for(j in (i+1):7){
    print((x[i]+x[j])/2)
  }
}

## [1] 7.5
## [1] 3.5
## [1] 5.5
## [1] 4
## [1] 6.5
## [1] 6
## [1] 6
## [1] 8
## [1] 6.5
## [1] 9
## [1] 8.5
## [1] 4
## [1] 2.5
## [1] 5
## [1] 4.5
## [1] 4.5
## [1] 7
## [1] 6.5
## [1] 5.5
## [1] 5
## [1] 7.5

Extra alternative

a<-c(5,10,2,6,3)
mean(a)

## [1] 5.2

var(a)

## [1] 9.7

g<-combn(x = a,m = 2)
g

##      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
## [1,]    5    5    5    5   10   10   10    2    2     6
## [2,]   10    2    6    3    2    6    3    6    3     3

colMeans(g)

##  [1] 7.5 3.5 5.5 4.0 6.0 8.0 6.5 4.0 2.5 4.5

mean(colMeans(g))

## [1] 5.2

var(colMeans(g))

## [1] 3.233333