Conditional expectations Let 2 - 0, 1)3, that is, all possible (ordered) triples of zeros and...
Let Ω = {0, 1} 3 , that is, all possible (ordered) triples of zeros and ones. Suppose that all outcomes have equal probability. We define three random variables X1, X2, and X3 on this space representing the first, second, and third digit, respectively. We also define X = X1 + X2 + X3. compute: E(E(X|X1)|X2)
Let S be the set of distinct ordered triples comprised of the numbers 1, 2, 3, 4. To say that the triple is distinct means that no number occurs twice in the triple. To say that the triple is ordered means that two triples in which the same numbers appear in a different order are considered to be different triples. Some of the elements of S are: 1,2,3), (1,2,4), (3,2,1), (3,2,4), (4,2,1), (4,3,2) We wish to list all of the...
(4) Consider rolling three dice. Let X1, X2, and X3 the values which appear on the three dice, respectively. Let Y be the maximum out of all three dice. (a) Find the conditional PMF py)xi (yr) (b) Find the probability that the maximum of all three dice is 4 given that the first die is a 3. (c) Find the probability that the maximum of all three dice is 3 given that the first die is a 3
(4) Consider...
(4) Consider rolling three dice. Let X1, X2, and X3 the values which appear on the three dice, respectively. Let Y be the maximum out of all three dice. (a) Find the conditional PMF py)xi (yr) (b) Find the probability that the maximum of all three dice is 4 given that the first die is a 3. (c) Find the probability that the maximum of all three dice is 3 given that the first die is a 3
(4) Consider...
Let X1,X2 and X3 be three discrete random variables withP[X1 = 0] = P[X1 = 1] = P[X2 = 0] = P[X2 = 1] = 1/2and P[X3 = 0] = 1.(i) Characterize all possible coupling between X1 and X2.(ii) Which coupling maximizes the correlation? Which coupling minimizes thecorrelation? Do you have an intuitive explanation why these couplings are theones that minimize/maximize the correlation?(iii) Which coupling makes the two random variables uncorrelated?(iv) Do the tasks (i) − (iii) but for X1...
Exercise 7. Let Xi, X2, . . . be independent, identically distributed rundorn variables uithEX and Var(X) 9, and let Yǐ = Xi/2. We also define Tn and An to be the sum and the sample mean, respectively, of the random variablesy, ,Y,- 1) Evaluate the mean and variance of Yn, T,, and A (2) Does Yn converge in probability? If so, to what value? 3) Does Tn converge in probability? If so, to what value? (4) Does An converge...
Let xi, i 1, 2, 3, , be a sequence of nonnegative numbers such that Σ x.-1 and consider the random variable X whose probability function is defined by: x, for x=x1, x2, X3, 0, for all other x What is the variance of X? i= 1
Concept Check: Conditional Quantile 1 point possible (graded) Let (X, Y) be a pair of RVs with joint density f (x, y) = x + y, over the sample space 12 = [0, 1]?. For a given x, what is the value qa (x) such that P[Y < 9a (x) |X = x] = 1 – a? That is, what is the conditional (1 – a)-quantile function (of x) of Y|X = x? The Shapes of Joint and Conditional Distributions...
2) Consider the sample space of three coin tosses: Ω = {HHH, HHT, HTH, HTT, THH, THT, TTH, TTT }. Assuming all elements to be equally likely, we assign P({ωi}) = 1/8, i = 1, 2, 3, 4, 5, 6, 7, 8. Define random variable to capture the second and third outcomes of the toss: X2 = { 0, if second outcome is T; 1, if second outcome is H and X3 = { 0, if third outcome is T;...
Let the mutually independent random variables X1, X2, and X3 be N(0, 1),N(2, 4), and N(−1, 1), respectively. Compute the probability that exactly two ofthese three variables are less than zero.