# Question

Using the background of Example 4.4-4, calculate the means and variances of X and Y.

## Answer to relevant Questions

In a college health fitness program, let X denote the weight in kilograms of a male freshman at the beginning of the program and Y denote his weight change during a semester. Assume that X and Y have a bivariate normal ...Let X and Y have a bivariate normal distribution with parameters μX = 10, σ2x = 9, μY = 15, σY2 = 16, and ρ = 0. Find (a) P(13.6 < Y < 17.2). (b) E(Y | x). (c) Var(Y | x). (d) P(13.6 < Y < 17.2 | X = 9.1). The lifetime (in years) of a manufactured product is Y = 5X0.7, where X has an exponential distribution with mean 1. Find the cdf and pdf of Y. Let X have a beta distribution with parameters α and β. (a) Show that the mean and variance of X are, respectively (b) Show that when α > 1 and β > 1, the mode is at x = (α − 1)/(α + β − 2). Let X1 and X2 be a random sample of size n = 2 from a distribution with pdf f(x) = 6x(1 − x), 0 < x < 1. Find the mean and the variance of Y = X1 + X2.Post your question

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