Let X be a random variable with E(X) = µ and V (X) = σ 2 . Let a and b be constants (fixed numbers) and define another random variable Y = aX + b. Find the E[Y ] and V [Y ] in terms of E(X) = µ and V (X) = σ 2 . From your results, tell whether adding or subtracting a constant to the random variable changes its variance.
5. A random variable X ∼ N (µ, σ2 ) is Gaussian distributed with mean µ and variance σ 2 . Given that for any a, b ∈ R, we have that Y = aX + b is also Gaussian, find a, b such that Y ∼ N (0, 1) Please show your work. Thanks!
= Var(X) and σ, 1. Let X and Y be random variables, with μx = E(X), μY = E(Y), Var(Y). (1) If a, b, c and d are fixed real numbers, (a) show Cov (aX + b, cY + d) = ac Cov(X, Y). (b) show Corr(aX + b, cY +d) pxy for a > 0 and c> O
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?
2. Let X be a Bernoulli random variable with probability of X -1 being a. a) Write down the probability mass function p(X) of X in terms of a. Mark the range of a (b) Find the mean value mx(a) EX] of X, as a function of a (c) Find the variance σ剤a) IX-mx)2) of X, as a function of a. (d) Consider another random variable Y as a function of X: Y = g(X) =-log p(X) where the binary...
If the random variable X has a mean of µ and a standard deviation σ, then the mean and standard deviation, respectively, of (X − µ)/σ are μ and σ. x¯ and s. 1 and 0. 0 and 1.
Let Xi, x,, ,X, be independent random variables with mean and variance σ . Let Y1-Y2, , Y, be independent random variables with mhean μ and variance a) Compute the expected value of W b) For what value of a is the variance of W a minimum? σ: Let W-aX + (1-a) Y, where 0 < a < 1.
Let Xi, x,, ,X, be independent random variables with mean and variance σ . Let Y1-Y2, , Y, be independent random...
X is a random variable with a lognormal distribution and that Y = ln(X) ∼ N(µ, σ2 ). Prove that µX = e ^ (µ+ (σ^2)/2 )
If X is a random variable such that E(X)=3 and V(X)=2, and if Y is a random variable such that Y=6+2X. Calculate the mean and variance of Y. a) E(Y)=12 b) V(Y)=
3. Let X be the height of Zebras, assume the X is a random variable with mean 10 and variance 20. Suppose Y is be the weight of Zebras, assume the Y is a random variable with mean 10 and variance 40. Let E(XY)-80 (a) Find the covariance and correlation between X and Y. Find the covariance and correlation between aX + b and cY + d. a,b,c, and d are unknown constants. Your answer can depend on them. (b)...
Compute the probability for a random variable X with µ=10 and σ=2. Calculate P(9 < X < 11).