Thread: can someone verify if I did this correctly ?

1. can someone verify if I did this correctly ?

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 !

2. The first one is OK
In the second one, I have no idea what these B's are.
Killer B's?

3. the B's are the regression coefficients. B(y/x) is the coefficient of X when Y is the response, and when B(x/y) it's the opposite.