W9 discussion

#A:

X = height, Y = error, X = 200 + Y

E(Y)=15(−2+−1+0+1+2)=0 E(X) = 200 + E(Y) = 200 :expected value = 200

V(Y)=15(−22−12+02+12+22)=105=2 V(X) = V(Y) = 2 : variance

#B:

E <- 200
V <- sqrt((1/18)*2)
V

## [1] 0.3333333

P199 <- ((199-E)/V)
P199

## [1] -3

P201 <- ((201-E)/V)
P201

## [1] 3

(0.5-dnorm(P199))*2 # probability in 18 independent measures= 0.99113

## [1] 0.9911363