Problem 10. Let X1, X2, . . . be random variables such that Xn → c in D holds for some number c. Show that Xn → c in P holds
Problem 10. Let X1, X2, . . . be random variables such that Xn → c...
Let X1, X2,...be a
sequence of random variables. Suppose that Xn?a in probability for
some a ? R. Show that (Xn) is Cauchy convergent in probability,
that is, show that for all
> 0 we have P(|Xn?Xm|> )?0 as n,m??.Is the converse true?
(Prove if “yes”, find a counterexample if “no”)
Problem 9. let X1, X2, ,Xn be independent 0,1) random variables. Set Is there a matrix M such that ド: 1 F(3/4) -3/4 holds with independent standard normal random variables Z.Z, Z? If so, calculate M
Problem 8. Let X1, X2, , Xn be independent ฆ(0,1) random variables. Let m,-1 for k 1,2,3. Are there numbers mi,m2, m3 such that n.y rn1 m1 a.S n3 m3 holds? If so, calculate these numbers.
4. Let X1, X2, . .. be independent random variables satisfying E(X) E(Xn) --fi. (a) Show that Y, = Xn - E(Xn) are independent and E(Yn) = 0, E(Y2) (b) Show that for Y, = (Y1 + . . + Y,)/n, <B for some finite B > 0 and VB,E(Y) < 16B. 16B 6B 1 E(Y) E(Y) n4 i1 n4 n3 (c) Show that P(Y, > e) < 0 and conclude Y, ->0 almost surely (d) Show that (i1 +...
Let Ņ, X1. X2, . . . random variables over a probability space It is assumed that N takes nonnegative inteqer values. Let Zmax [X1, -. .XN! and W-min\X1,... ,XN Find the distribution function of Z and W, if it suppose N, X1, X2, are independent random variables and X,, have the same distribution function, F, and a) N-1 is a geometric random variable with parameter p (P(N-k), (k 1,2,.)) b) V - 1 is a Poisson random variable with...
8. Let X1, X2,...,X, U(0,1) random variables and let M = max(X1, X2,...,xn). - Show that M. 1, that is, M, converges in probability to 1 as n o . - Show that n(1 - M.) Exp(1), that is, n(1 - M.) converges in distribution to an exponential r.v. with mean 1 as n .
Let X1, X2, · · · be independent random variables, Xn ∼ U(−1/n, 1/n). Let X be a random variable with P(X = 0) = 1. (a) what is the CDF of Xn? (b) Does Xn converge to X in distribution? in probability?
3. Let X1, X2, . . . , Xn be random variables with a common mean μ. Sup- pose that cov[Xi, xj] = 0 for all i and A such that j > i+1. If 仁1 and 6 VECTORS OF RANDOM VARIABLES prove that = var X n(n- 3)
1. Let X, X1, X2, ... be random variables defined on the same space. Assume that Xn + X. Assume further that there is a random variable Y with E[Y] < o such that P(|Xn] <Y) = 1 for each n. Show that lim E[Xn] = E[X]. n-
Let X1 and X2 be random variables, not necessarily independent. Show that E [X1 + X2] = E [X1] + E [X2]. You may assume that X1 and X2 are discrete with a joint probability mass function for this problem, while the above inequality is true also for continuous random variables.