Original post by darren86
If X and Y are independent random variables then
Var(X+Y)=Var(X)+Var(Y)
Now if X and Y are independent and identically distributed
Var(X+Y)=Var(2X)=4Var(X)
but using the first formula we would get 2Var(X)
why is this?
Var(X+Y)=Var(X)+Var(Y)
Now if X and Y are independent and identically distributed
Var(X+Y)=Var(2X)=4Var(X)
but using the first formula we would get 2Var(X)
why is this?
If you have X+X, then the second X is not independent of the first X.
Original post by ghostwalker
If you have X+X, then the second X is not independent of the first X.
If you have X+X, then the second X is not independent of the first X.
Thanks!
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