Assume that Y = 2X + 1. Assume that E(Y) = 5 and var(Y) = 25. Find E(X) and E(X^2).
Assume X, Y are independent with EX = 1 EY = 2 Var(X) = 22 Var(Y) = 32 Let U = 2X + Y and V = 2X – Y. (a) Find E(U) and E(V). (b) Find Var(U) and Var(V). (c) Find Cov(U,V).
Y=2x+1, find the pmf of y ,E(y) and var(y) Zhejiang University of Science and Technology 2. The joint pmf of X and Y is 2 6 0 4 0 Find the marginal distribution of Y and E(XY).
Suppose X~N(1; 4) and Y = e^2X. Compute E[Y ] and Var(Y )
Suppose XX and YY are independent random variables for which Var(X)=7Var(X)=7 and Var(Y)=7.Var(Y)=7. (a) Find Var(X−Y+1).Var(X−Y+1). (b) Find Var(2X−3Y)Var(2X−3Y) (c) Let W=2X−3Y.W=2X−3Y. Find the standard deviaton of W.W.
For the following problems assume y-Xß + ε and assume E(e)-0 and var(e)-σ21 1. We are often interested in estimating where r. is a (p+ 1)x 1 vector of predictors. We will find that a reasonable estimator is Find var(y*).
Given Var(X) = 4, Var(Y) = 1, and Var(X+2Y) = 10, What is Var(2X-Y-3)? I know the answer is 15, I'm particularly interested in the specific steps involved with finding the cov(X,Y) in this problem. Please explain in detail, step by step how you come to cov(X,Y) = 0.5 in this equation. Please include any formulas you would need to use to find the cov(X,Y) in this equation.
4. Assume X ~ Uniform(0, 1) and let Y = 2X+1 and Z = X2 + 1. (a) Find Cov(X,Y), Var(X+Y), Var(X - Y) and Corr(X,Y). (b) Find Cov(X, Z), Var(X + Z), Var(X – Z) and Corr(X, Z).
(2. Assume that X, Y, and Z are random variables, with EX) = 2, Var(X) = 4, E(Y) = -1, Var(Y) = 6, E(Z) = 4, Var(Z) = 8,Cov(X,Y) = 1, Cov(X, Z) = -1, Cov(Y,Z) = 0 Find E(3X + 4y - 62) and Var(3x + 4y - 62).
For the following problems assume y = Χβ + ε and assume E(e) 0 and var(e) σ21. 3. Show that έ (1-X (XTX)-XT) ε. (Hint: Use the assumption that y + ε)
For the random variables X and Y having E(X) = 1, E(Y) = 2, Var (X) = 6, Var (Y) = 9, and Pxy = -2/3. Find a) The covariance of X and Y. b) The correlation of X and Y. c) E(X2) and E(Y2).