For two independent variables X and Y, Var(aX-bY)= a2 var(X)+b2 var(Y).
So
Var(4X-3Y)= Var(4X)+var(3Y)=16 var(X)+ 9 var(Y)
=16*13+9*37.6= 546(rounded to nearest whole number)
Question 5 If Var(X) = 13 and Var(Y) = 37.6 and X and Y are independent...
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.
5)Suppose that X ∼ N(-1.9,2.7), Y ∼ N(3.5,1.4), and Z ∼ N(1.2, 1.0) are independent random variables. Find the probability that 2.2X + 3Y + 4Z ≥ 8.8. Round your answer to the nearest thousandth. 6) Suppose that X ∼ N(-2.0,2.6), Y ∼ N(3.0,2.0), and Z ∼ N(1.7, 0.5) are independent random variables. Find the probability that |3.1X + 3Y + 4Z| ≥ 8.0. Round your answer to the nearest thousandth.
Let X, Y be independent random variables with E[X] = E[Y] = 0 and ox = Oy = 5. Then Var(2x+3Y) = 1. True False
Let X, Y be independent random variables with E[X] = E[Y] = 0 and ox = oy = 5. Then Var(2x +3Y) = 1. True False
For random variables X, Y, and Z, Var(X) = 4, Var(Y) = 9, Var(Z) = 16, E[XY] = 6, E[XZ] = −8, E[Y Z] = 10, E[X] = 1, E[Y ] = 2 and E[Z] = 3. Calculate the followings: (b) Cov(−3Y , −4Z ). (d) Var(Y − 3Z). (e) Var(10X + 5Y − 5Z).
Qs. Random variables X and Y have Joins PDE 0 otherwise (a) What is Cov[X, YT (b) What is Var[X +Y]? (c) Are X and Y independent? Prove your answer. Qs. Random variables X and Y have Joins PDE 0 otherwise (a) What is Cov[X, YT (b) What is Var[X +Y]? (c) Are X and Y independent? Prove your answer.
der two independent random variables X and Y with the following 11. Consi means and standard deviations: = 60; ơv_ 15. (a) Find E(x + Y), Var(X + Y), E(X Y), Var(X - Y). (b) If x* and Y* are the standardized r.v.'s eorresponding to the r.v.'s X and Y, respectively, determine E(X* + Y*), E(X*-Y*), Var(X* Y*), Var(x* - Y*) der two independent random variables X and Y with the following 11. Consi means and standard deviations: = 60;...
Obtain E(Z|X), Var(Z|X) and verify that E(E(Z|X)) =E(Z), Var(E(Z|X))+E(Var(Z|X)) =Var(Z) 3. Let X, Y be independent Exponential (1) random variables. Define 1, if X Y<2 Obtain E (Z|X), Var(ZX) and verify that E(E(Zx)) E(Z), Var(E(Z|X))+E(Var(Z|X)) - Var(Z)
5. Suppose X and Y are random variables such that E(X)=E(Y) = θ, Var(X) = σ and Var(Y)-吆 . Consider a new random variable W = aX + (1-a)Y (a) Show that W is unbiased for θ. (b) If X and Y are independent, how should the constant a be chosen in order to minimize the variance of W?
Show steps, thanks ·Additional Problem 13. For random variables X and Y it is given that Ox = 2, ơY = 5, and pxy 3 (a) Find Cov(Xx,y) (b) Var(4X-2Y7 Answers: (a) -. (b) 002 10652 li 3 . Additional Problem 14. Suppose Xi and X2 are independent random variables that have exponential distribution with β 4. (a) Find the covariance and correlation between 5Xi + 3X, and 7Xi-2X. (b) Find Var-5X2-2