Question Eight:
i) Show using convolutions or moment generating functions that ;
(a) if ? and ? are independent random variables and ? has a ?? 2 distribution and ? has a ?? 2 distribution, then ? + ? has a ??+? 2 distribution.
(b) If ?~???(?) and ?~???(?) are independent random variables, then ? + ? has a ???(? + ?) distribution.
ii) A company issues questionnaires to clients to obtain feedback on the clarity of their brochure. It is thought that 5% of clients do not find the brochure helpful. Calculate the approximate probability that in a sample of 1,000 responses, the number, ?, of clients who do not find the brochure helpful satisfies 40 < ? < 70.
Question Eight: i) Show using convolutions or moment generating functions that ; (a) if ? and...
0.4. Suppose that Yi and Y2 are discrete independent random variables with the following moment generating functions: 6 10 102 I. Find the mean and variance of Yi 1-
0.4. Suppose that Yi and Y2 are discrete independent random variables with the following moment generating functions: 6 10 102
I. Find the mean and variance of Yi 1-
The moment generating function ф(t) of random variable X is defined for all values of t by et*p(x), if X is discrete e f (x)dx, if X is continus (a) Find the moment generating function of a Binomial random variable X with parameters n (the total number of trials) and p (the probability of success). (b) If X and Y are independent Binomial random variables with parameters (n1 p) and (n2, p), respectively, then what is the distribution of X...
3. (4 points) The random variables X and Y are independent and have moment generating functions Find Var(X).x (t) =er-2t and Mr(t)=e3t2+tid t a) Find MGF of Z Find Var(Z). Find joint MGF of X and Z, i.e. Mxz(t1,t2) 2X-Y c) d)
9. (9 pts) The random variable r-Gamma(x-2, β-4). functions to prove that the moment generating function for the random variable W mw(t) (1-12t)2. Use the method of moment-generating 3Y +5is eSt 10, (9 pts) Suppose that Y has a gamma distribution with α-n/2 for some positive integer n and β equal to some specified value. Use the method of moment-generating functions to prove that W- 2Y /g has a Chi-squared distribution with n degrees of freedom. Make sure you show...
4. The moment generating function of the normal distribution with parameters μ and σ2 is (t) exp ( μ1+ σ2t2 ) for -oo < t oo. Show that E X)-ψ(0)-μ and Var(X)-ψ"(0)-[ty(0)12-σ2. 5. Suppose that X1, X2, and X3 are independent random variables such that E[X]0 and ElX 1 for i-12,3. Find the value of E[LX? (2X1 X3)2] 6. Suppose that X and Y are random variables such that Var(X)-Var(Y)-2 and Cov(X, Y)- 1. Find the value of Var(3X -...
Can we find this without use of the moment
generating function?
3. (15 pts) Let Xị and X2 be two independent random variables that follow standard normal distribution. The PDF of a standard normal distribution is given by f(t)= exp-/2; - <t<0.. i) Find the joint PDF of V = X1 + X2 and Y2 = X1 - X). ii) Prove that Yi and Y2 are independent. R ONALEN SON
The moment generating function (MGF) for a random variable X is: Mx (t) = E[e'X]. Onc useful property of moment generating functions is that they make it relatively casy to compute weighted sums of independent random variables: Z=aX+BY M26) - Mx(at)My (Bt). (A) Derive the MGF for a Poisson random variable X with parameter 1. (B) Let X be a Poisson random variable with parameter 1, as above, and let y be a Poisson random variable with parameter y. X...
Problems binomial random variable has the moment generating function ψ(t)-E( ur,+1-P)". Show, that EIX) np and Var(X)-np(1-P) using that EXI-v(0) and Elr_ 2. Lex X be uniformly distributed over (a b). Show that EX]- and Varm-ftT using the first and second moments of this random variable where the pdf of X is () Note that the nth i of a continuous random variable is defined as E (X%二z"f(z)dz. (z-p?expl- ]dr. ơ, Hint./ udv-w-frdu and r.e-//agu-VE. 3. Show that 4 The...
3. Use the probability generating function Px)(s) to find (a) E[X(10)] (b) VarX(10)] (c) P(X(5)-2) . ( 4.2 Probability Generating Functions The probability generating function (PGF) is a useful tool for dealing with discrete random variables taking values 0,1, 2, Its particular strength is that it gives us an easy way of characterizing the distribution of X +Y when X and Y are independent In general it is difficult to find the distribution of a sum using the traditional probability...
problems binomial random, veriable has the moment generating function, y(t)=E eux 1. A nd+ 1-p)n. Show that EIX|-np and Var(X) np(1-p) using that EIX)-v(0) nd E.X2 =ψ (0). 2. Lex X be uniformly distributed over (a b). Show that ElXI 쌓 and Var(X) = (b and second moments of this random variable where the pdf of X is (x)N of a continuous randonn variable is defined as E[X"-广.nf(z)dz. )a using the first Note that the nth moment 3. Show that...