1. Var(x)=4

find Var((1-x)/2)

I did: Var((1-x)/2) = Var(0.5*(1-x)) = 0.25*Var(1-x) = 0.25*Var(-x) =

0.25*Var(x)=0.25*4=1

2. regression question: B(y/x) = -0.625 , B(x/y)=-0.4 . Find r.

I did:

B(y/x)=r*(Sy/Sx) B(x/y)=r*(Sx/Sy)

-0.625=r*s

-0.4 = r/s

.

.

.

r=-0.5

Are these two correct ?

thanks a million !