Answer:
Given that:
Suppose the random variables X,Y and Z are related through the model
Y = 2 + 2X + Z,
where Z has mean 0 and variance σZ2 = 16 and X has variance σX2 = 9. Assume X and Z are independent, the find the covariance of X and Y and that of Y and Z. (Hint: write Cov(X,Y ) = Cov(X,2 + 2X + Z)
Cov(X,Y) = Cov(X,2+2X+Z)
Cov(X,Y) = Cov(X,2) + 2*Cov(X,X) + Cov(X,Z)
Cov(X,Y) = 0 + 2*9+0
Cov(X,Y) = 18
(Cov (X,X) = Var(X) ; Covariance of two independent variables is zero. So Cov(X,Z) = 0)
Cov(Z,Y) = Cov(Z,2+2X+Z)
Cov(Z,Y) = Cov(Z,2) + 2*Cov(Z,X) + Cov(Z,Z)
Cov(Z,Y) = 0 + 2*0+16
Cov(Z,Y) = 16
5. Suppose the random variables X, Y and Z are related through the model Y =...
Suppose the random variables X, Y and Z are related through the model Y = 2 + 2X + Z, where Z has mean 0 and variance σ2 Z = 16 and X has variance σ2 X = 9. Assume X and Z are independent, the find the covariance of X and Y and that of Y and Z. Hint: write Cov(X, Y ) = Cov(X, 2+2X+Z) and use the propositions of covariance from slides of Chapter 4. Suppose the...
5. Suppose the random variables X, Y and Z are related through the model Y = 2 + 2X + Z, where Z has mean 0 and variance o2 = 16 and X has variance of = 9. Assume X and Z are independent, the find the covariance of X and Y and that of Y and Z. Hint: write Cov(X, Y) = Cov(X, 2+2X+Z) and use the propositions of covariance from slides of Chapter
If the random variables X, Y, and Z have the means ji x = 3, My = -2, and uz = 2, the variances of = 3, o = 3, o2 = 2, the covariances cov(X,Y) = -2, cov(X, Z) = -1, and cov(Y,Z) = 1, U = Y - Z, and V = X - Y + 2Z. (a) Find the mean and the variance of U and V. (b) Find the covariance of U and V.
If the random variables X, Y, and Z have the means ux = 3, uy = -2, and uz = 2, the variances o = 3, o = 3, o2 = 2, the covariances cov(X,Y) = -2, cov(X, Z) = -1, and cov(Y,Z) = 1, U = Y - Z, and V = X - Y +2Z. (a) Find the mean and the variance of U and V, respectively. (b) Find the covariance of U and V.
10.3.8 Suppose that Y = E(Y | X) + Z, where X, Y and Z are random variables. (a) Show that E (Z | X) = 0. (b) Show that Cov(E(Y | X), Ζ) = 0. (Hint. Write Z-Y-E(YİX) and use Theo- rems 3.5.2 and 3.5.4.) (c) Suppose that Z is independent of X. Show that this implies that the conditional distribution of Y given X depends on X only through its conditional mean. (Hint: Evaluate the conditional distribution function...
Suppose X, Y and Z are independent standard normal random variables. Then W = 2X + Y - Z is a random variable with mean 0 and variance 2, but not necessarily normal distributed. a normal random variable with mean 0 and variance 4. O a random variable with mean 0 and variance 4, but not necessarily normal distributed. a random variable with mean 0 and variance 6, but not necessarily normal distributed. a normal random variable with mean 0...
Suppose X, Y and Z are independent standard normal random variables. Then W = 2X + Y - Z is a random variable with mean 0 and variance 2, but not necessarily normal distributed. a normal random variable with mean 0 and variance 4. O a random variable with mean 0 and variance 4, but not necessarily normal distributed. a random variable with mean 0 and variance 6, but not necessarily normal distributed. a normal random variable with mean 0...
5. The means, standard deviations, and covariance for random variables X, Y, and Z are given below. Ux= 3, uy = 5, uz = 7 Ox= 1, OY = 3, oz = 4 cov(X, Y) = 1, cov (X, Z) = 3, and cov (Y,Z) = -3 T= X-28 +3 Z var(T) = 16. For a random variable X with an unknown distribution. The mean of X is u = 22 and tting a randomly chosen value of X
Suppose X, Y and Z are three different random variables. Let X obey Bernoulli Distribution. The probability distribution function is p(x) = Let Y obeys the standard Normal (Gaussian) distribution, which can be written as Y ∼ N(0, 1). X and Y are independent. Meanwhile, let Z = XY . (a) What is the Expectation (mean value) of X? (b) Are Y and Z independent? (Just clarify, do not need to prove) (c) Show that Z is also a standard...
Suppose that Z = Σ 1 id with exponential distribution ( 5), and the random variables Y, are id with mean 0.2 and variance 0.05. If X's are independent of Y's, find an approximation for the pdf of Z using the central limit theorem. Xi + Σ 1 Y, where the random variables Xi are Suppose that Z = Σ 1 id with exponential distribution ( 5), and the random variables Y, are id with mean 0.2 and variance 0.05....