Given a random variable X, with standard deviation σx, and a random variable Y = a + bX, show that if b < 0, the correlation coefficient, pxy = -1, and if b > 0, pxy = 1. What is the correlation coefficient if a/b=π and a=(1+√2)/5 ?
Given a random variable X, with standard deviation σx, and a random variable Y = a...
Random variable X has mean Ux=24 and standard deviation σx =6. Randon variable Y has mean Uy =14 and standard deviation σY = 4. A new random variable Z was formed, where Z=X+Y. What can we conclude about X, Y, and Z with certainty? That is, which one is true?
If X is a random variable with mean -3 and standard deviation 2, Y is a random variable with mean 5 and standard deviation 3, and the correlation between X and Y is ρ Corr(X, Y) = .8, find Cov(2x-Y, X + 5Y). If X is a random variable with mean -3 and standard deviation 2, Y is a random variable with mean 5 and standard deviation 3, and the correlation between X and Y is ρ Corr(X, Y) =...
Random variable (20) Z X+Y is a random variable equal to the sum of two continuous random variables X and Y. X has a uniform density from (-1, 1), and Y has a uniform density from (0, 2). X and Y may or may not be independent. Answer these two separate questions a). Given that the correlation coefficient between X and Y is 0, find the probability density function f7(z) and the variance o7. b). Given that the correlation coefficient...
4. Standard deviation and risk. The standard deviation o(X) of a random variable is the square root of the variance that is o(X) = Var(X). It characterizes the "spread" of the random variable X. If a random variable X has expected value p and standard deviation o, then X takes values which are on average at distance o from u. Imagine you have the choice to invest in two stock funds: an American fund with a rate return X and...
Problem 8: Let X and Y be continuous random variables. The joint density of X and Y is given by: fxy (x, y)2 if 0 yx< 1. Find the correlation coefficient of X and Y, pxy. Problem 8: Let X and Y be continuous random variables. The joint density of X and Y is given by: fxy (x, y)2 if 0 yx
Let X and Y be jointly continuous random variables having joint density fxy(x,y) = 2 y + x1, x>0, y> O otherwise Find Cov(X,Y) and Determine the correlation coefficient PXY O A. Cov(X,Y) = -1/36 , PXY=-1/2 OB. Cov(X,Y) = -1/18, PXY= 1/3 OC. Cov(X,Y) = -1/36 , PXY=0 OD. Cov(X,Y) = 1/12, PXY--1/2
Given a population standard deviation of 40, calculate the standard deviation of the mean (σX) given the following sample sizes (show all your work): 7) N = 60
Let a random variable X be uniformly distributed between −1 and 2. Let another random variable Y be normally distributed with mean −8 and standard deviation 3. Also, let V = 22+X and W = 13+X −2Y . (a) Is X discrete or continuous? Draw and explain. (b) Is Y discrete or continuous? Draw and explain. (c) Find the following probabilities. (i) The probability that X is less than 2. (ii) P(X > 0) (iii) P(Y > −11) (iv) P...
(4pt) The variance of random variable X is 4 and the variance of random variable Y is 16. The correlation coefficient between the two random variables X and Y is 0.9. (a) (1pt) Find the covariance between X and Y. (b) A new random variable Z is given by Z = 5x + 1. Find the covariance between X and Z. (1pt) Find the covariance between Y and Z. (2pt)
A random variable X has an expected value of 10 with a standard deviation of 5. Let Y= 5 -2*X be another random variable. Find the expected value of Y and its standard deviation