The following relates to Problems 21 and 22. Let X ~ NĢi 1, σ2-1), Y ~ NĢı = 2,02-9) and ρχ.Y = 0.5 (recall that ρΧΥ stands for the correlation coefficient of X and Y) Problem 21: Find COV(X, Y) and...
The following relates to Problems 26 - 27. Let X, Y be random variables and b a number. Problem 26: Find E (Y – bX)21 [1] E(X)b2 – 2E(XY)b+E(Y2); [2] E(X2)62 – E(Y); [3] -2E(XY)b+E(Y); [4] E(Y2); 151 E(X2)62 [6] Problem 27: Find b that minimizes E [(Y – bx)2] [1] E(YP); [2] E(X) – E(Y); [3] –2E(XY) + E(Y2); [4] ; [5]
4.2 The Correlation Coefficient 1. Let the random variables X and Y have the joint PMF of the form x + y , x= 1,2, y = 1,2,3. p(x,y) = 21 They satisfy 11 12 Mx = 16 of = 12 of = 212 2 My = 27 Find the covariance Cov(X,Y) and the correlation coefficient p. Are X and Y independent or dependent?
Suppose (X,Y) follows a trinomial distribution (5, 1/3, 1/4). a. Find E(X) b. Find E(Y) c. Find Var(X) d. Find Var(Y) e. Find Cov (X,Y) f. Find p (correlation coefficient)
7. Find cov(X, Y) 8. Are the random variables X, Y independent? Justify answer Edit : do not solve number 1, I already solved. C=3/32 Use this information for problems 1 -8: Let X, Y be two continuous random variables and let f(x, y)2y + xy?) over the range O< x<2 and 0< y< 2. Determine the v function alue of the constant c that makes this function a joint probability density 1. Use this information for problems 1 -8:...
Problem 2 Suppose two continuous random variables (X, Y) ~ f(x,y). (1) Prove E(X +Y) = E(X)+ E(Y). (2) Prove Var(X + Y) = Var(X) + Var(Y)2Cov(X, Y). (3) Prove Cov(X, Y) E(XY)- E(X)E(Y). (4) Prove that if X and Y are independent, i.e., f(x, y) Cov(X, Y) 0. Is the reverse true? (5) Prove Cov (aX b,cY + d) = acCov(X, Y). (6) Prove Cov(X, X) = Var(X) fx (x)fy(y) for any (x,y), then =
The (population) correlation coefficient, called p, is discussed in Section 4.5.2 of your text. Given two random variables X and Y with some joint distribution and means ux and uy, p= Corr(X,Y) = Cov(X, Y), where σχσY oſ = Var(x), of = Var(y) and Cov(X,Y) = E[(X - MX)(Y – My)] Given data, we can estimate p. Suppose that (X1,Y1), ..., (Xn, Yn) are independent and iden- tically distributed (i.i.d.) pairs of realizations of the random variables (X, Y). How...
Consider the following small data set. x-11 y- 22 , x-15 y-16 , x-12 y-27 , x-6 y-26 ,x-5 y- 21 Find the linear correlation coefficient. r=
14. Random variables X and Y have a density function f(x, y). Find the indicated expected value. f(x, y) = (xy + y2) 0<x< 1,0 <y<1 0 Elsewhere {$(wyty E(x2y) = 15. The means, standard deviations, and covariance for random variables X, Y. and Z are given below. LIX = 3. HY = 5. Az = 7 Ox= 1, = 3, oz = 4 cov(X,Y) = 1, cov (X, Z) = 3, and cov (Y,Z) = -3 T = X-2...
for 1 Sx soo and 2. Suppose that X and Y are continuous and jointly distributed by the function f(x,y) = 1 Sy S. PAY ATTENTION TO THE SUPPORT REGION. a. Find the marginals for X and Y. b. Find the conditional probability density functions g(xly) and hylx). C. Determine whether or not X and Y are independent based on your results above. d. Calculate P(X+Y<5 Y = 3). e. Find E[X] f. Find E[Y] 8. Find E[XY] h. Find...
problems binomial random, veriable has the moment generating function, y(t)=E eux 1. A nd+ 1-p)n. Show that EIX|-np and Var(X) np(1-p) using that EIX)-v(0) nd E.X2 =ψ (0). 2. Lex X be uniformly distributed over (a b). Show that ElXI 쌓 and Var(X) = (b and second moments of this random variable where the pdf of X is (x)N of a continuous randonn variable is defined as E[X"-广.nf(z)dz. )a using the first Note that the nth moment 3. Show that...