probml
Book 1, Solution in pdf to 3.5
Not sure if this is the correct place to report this issue for this:
It says: E [Y ] = E [W X] = E [X] E [X] = 0
Should say:
E [Y ] = E [W X] = E [W] E [X] = 0
I'll clarify the difference with bold font:
current: E [Y ] = E [W X] = E [X] E [X] = 0
proposed: E [Y ] = E [W X] = E [W] E [X] = 0
E[W] and E[X] are both 0, so the original equality is not wrong, I suppose. Or maybe I'm not understanding how you go from E[W X] to E[X] E[X] symbolically. But it seems more straight forward to me to move from E[W X] to E[W] E[X] (which we can do when X and W are independent) than to E[X] E[X].
Does that make sense? Or am I missing something?
Oh I see. It's just a typo. It should be E [Y ] = E [W X] = E [W] E [X] = 0.