Suppose X1, X2, . . . , Xn (n ≥ 5) are i.i.d. Exp(µ)
with the density f(x) = 1
µ
e
−x/µ for x > 0.
(a) Let ˆµ1 = X. Show ˆµ1 is a minimum variance unbiased
estimator.
(b) Let ˆµ2 = (X1 +X2)/2. Show ˆµ2 is unbiased. Calculate V
ar(ˆµ2). Confirm V ar(ˆµ1) < V ar(ˆµ2).
Calculate the efficiency of ˆµ2 relative to ˆµ1.
(c) Show X is consistent and sufficient.
(d) Show ˆµ2 is not consistent and not sufficient. (Hint: X1 +
X2)/2 ∼ Γ(2,
β
2
))
X1, X2, . . . , Xn i.i.d. ∼ N (µ, σ2 ). Assume µ is known; show
that ˆθ = 1 n Pn i=1(Xi− µ) 2 is the MLE for σ 2 and show that it
is unbiased.
Exactly 6.4-2. Xi, X2, . . . , xn i d. N(μ, μ)2 is the MLE for σ2 and show that it is unbiased. r'). Assume μ is known; show that θ- n Ση! (X,-
Suppose X1, X2, . . . , Xn are i.i.d. Exp(µ) with the density f(x) = for x>0 (a) Use method of moments to find estimators for µ and µ^2 . (b) What is the log likelihood as a function of µ after observing X1 = x1, . . . , Xn = xn? (c) Find the MLEs for µ and µ^2 . Are they the same as those you find in part (a)? (d) According to the Central Limit...
Let X1,X2,...,Xn denote independent and identically distributed random variables with mean µ and variance 2. State whether each of the following statements are true or false, fully justifying your answer. (a) T =(n/n-1)X is a consistent estimator of µ. (b) T = is a consistent estimator of µ (assuming n7). (c) T = is an unbiased estimator of µ. (d) T = X1X2 is an unbiased estimator of µ^2. We were unable to transcribe this imageWe were unable to transcribe...
Let X1, ..., Xn be i.i.d. [Recall that i.i.d. stands for independent and identically distributed.] Since X1, ..., Xn all have the same distribution, they have the same expected value and variance. Let E(X1) = µ and V ar(X1) = σ 2 . Find the following in terms of µ and σ 2 . (a) E(X2 1 ). Note this is not µ 2 ! (b) E( Pn i=1 X2 i /n). (c) Now, define W by W = 1...
Q3 Suppose X1, X2, ..., Xn are i.i.d. Poisson random variables with expected value ). It is well-known that X is an unbiased estimator for l because I = E(X). 1. Show that X1+Xn is also an unbiased estimator for \. 2 2. Show that S2 (Xi-X) = is also an unbaised esimator for \. n-1 3. Find MSE(S2). (We will need two facts) E com/questions/2476527/variance-of-sample-variance) 2. Fact 2: For Poisson distribution, E[(X – u)4] 312 + 1. (See for...
Q2 Suppose X1, X2, ..., Xn are i.i.d. Bernoulli random variables with probability of success p. It is known ΣΧ; is an unbiased estimator for p. that = n 2. Suggest an unbiased estimator for pa. (Hint: use the fact that the sample variance is unbiased for variance.) 3. Show that p= ΣΧ,+2 n+4 is a biased estimator for p. 4. For what values of p, MSE) is smaller than MSE)?
Q2 Suppose X1, X2, ..., Xn are i.i.d. Bernoulli random variables with probability of success p. It is known that p = ΣΧ; is an unbiased estimator for p. n 1. Find E(@2) and show that p2 is a biased estimator for p. (Hint: make use of the distribution of X, and the fact that Var(Y) = E(Y2) – E(Y)2) 2. Suggest an unbiased estimator for p2. (Hint: use the fact that the sample variance is unbiased for variance.) Xi+2...
Let X1, X2, ......
Xn be a random sample of size n from
EXP()
distribution ,
, zero , elsewhere.
Given, mean of distribution
and variances
and mgf
a) Show that the mle
for
is
. Is
a consistent estimator for
?
b)Show that Fisher information
. Is mle of
an efficiency estimator for
? why or why not? Justify your answer.
c) what is the mle estimator of
? Is the mle of
a consistent estimator for
?
d) Is...
Suppose that X1, X2, ..., Xn are i.i.d. from Unif[α, 0]. (a) Find ˆαMM, which is the estimator using method of moments. (b) Compute E(ˆαMM) and V ar(ˆαMM) (c) Find ˆαML, which is the estimate using maximum likelihood method. (d) Determine the density of X(1), the smallest of X1, · · · , Xn, by solving the following: i. Find P(X(1) ≥ x) as a function of x, where x ≥ 0. (Hint: X(1) is defined to be the smallest....
5. Let X ∼ Exp(λ) with λ unknown, and suppose X1, X2 is a random sample of size 2. Show that M = sqrt( X1 · X2 ) is a biased estimator of 1/λ and modify it to create an unbiased estimator. (Hint: During your journey, you’ll need the help of the gamma distribution, the gamma function, and the knowledge that Γ(1/2) = √ π.)