applied statistics

1

1. Let X1, X2, ..., Xn denote independent random variables all with the same probability density function. Suppose E(X1) = 2. Find the expected value of X1 + X2+ ... + Xn Vn (a) 2 (b) 2vn (c) 2/ Vn (d) 2 (e) 2n2. Let X1, X2, X3 be independent random variables all with the same probability mass function. Suppose var ( X1 ) = 2. Find the variance of X1 + 2X2 +3X3 (a) 6n (b) 14n (C 12 (d) 2/3 (e) 28