Problem 4. Gaussian Random Variables
Let X be a standard normal random variable. Let Y be a continuous random variable such that
f_{Y|X}(y|x) = frac{1}{sqrt{2pi}} expleft(-frac{(y+2x)^2}{2}
ight).
1. Find E[Y|X = x] (as a function of x, in standard notation) and E[Y].
E[Y|X = x] =
E[Y] =
2. Compute Cov(X, Y).
Cov(X, Y) =
3. The conditional PDF of X given Y = y is of the form
alpha(y) exp{-quadratic(x, y)}
By examining the coefficients of the quadratic function in the exponent, find E[X | Y = y] and Var(X | Y = y).
E[X | Y = y] =
Var(X | Y = y) =