Let X1. . . . Xn be i.i.d f(x; θ) = θ(1 − θ)^x x =...
Let X1. . . . Xn be i.i.d f(x; θ) = θ(1 − θ)^x x = 0.. Is there
a function of θ for which there exists an unbiased estimator of θ
whose variance achieves the CRLB? If so, find it
Let X1, ..., Xn be i.i.d random variables with the density
function f(x|θ) = e^(θ−x) , θ ≤ x. a. Find the Method of Moment
estimate of θ b. The MLE of θ (Hint: Think carefully before taking
derivative, do we have to take derivative?)
Let X1,...,Xn be i.i.d. N(θ,1), where θ ∈ R is the
unknown parameter.
(a) Find an unbiased estimator of θ^2 based on
(Xn)^2.
(b) Calculate it’s variance and compare it with the Cram
́er-Rao lower bound.
Suppose X1; : : : ; Xn is i.i.d Exponential distribution with
density
f(xjθ) = (1/θ) * e(-x/θ); 0 ≤ x < 1; θ > 0:
(a) Find the UMVUE (the best unbiased estimator) of θ.
(b) What is the Cramer-Rao lower bound of all unbiased estimator of
all unbiased estimator
of θ. Does the estimator from (a) attain the lower bound? Justify
your answer.
(c) What is the Cramer-Rao lower bound of all unbiased estimator of
θ^2?
3
(d)...
Let X1, . . . , Xn be i.i.d. samples from Uniform(0, θ). Show
that for any α ∈ (0, 1), there is a cn,α, such that
[max(X1,...,Xn),cn,α max(X1,...,Xn)] is a 1−α confidence interval
of θ.
For a fixed θ>0, let X1,X2,…,Xn be i.i.d., each with the beta
(1,θ) density.
i) Find θ^ that is the maximum likelihood
estimate of θ.
ii) Let X have the beta (1,θ) density. Find the
density of −log(1−X). Recognize this as one of the famous ones and
provide its name and parameters.
iii) Find f that is the density of the MLE θ^
in part (i).
Let X1, X2, · · · , Xn be iid samples from density:
f(x) = {θx^(θ−1), if 0 ≤ x ≤ 1}
0 otherwise
Find the maximum likelihood estimate for θ. Explain, using
Strong Law of Large Numbers, that this maximum likelihood estimate
is consistent.
Let X1, ..., Xn be iid with pdf f(x; θ) = (1/ x√ 2π)
e(-(logx- theta)^2) /2 Ix>0 for θ ∈ R.
(a) (15 points) Find the MLE of θ.
(b) (10 points) If we are testing H0 : θ = 0 vs Ha :
θ != 0. Provide a formula for the likelihood ratio test statistic
λ(X).
(c) (5 points) Denote the MLE as ˆθ. Show that λ(X) is can be
written as a decreasing function of | ˆθ|...
Suppose X1, ..., Xn are i.i.d. from an exponential distribution
with mean θ. If we are testing H0 : θ = θ0 vs
Ha : θ > θ0. Suppose we reject H0 when
( X¯n/ θ0) > 1 + (1.645/
√n)
(a) (10 points) Calculate the power function G(ζ). You may leave
your answer in terms of the standard normal cdf Φ(x).
(b) (5 points) Is this test consistent?
1. Let X1, X2 be i.i.d with this distribution: f(x) = 3e cx, x ≥
0 a. Find the value of c
b. Recognize this as a famous distribution that we’ve learned in
class. Using your knowledge of this distribution, find the t such
that P(X1 > t) = 0.98.
c. Let M = max(X1, X2). Find P(M < 10)