LOYOLA COLLEGE (AUTONOMOUS), CHENNAI –600 034
B.Sc., DEGREE EXAMINATION – STATISTICS
FIFTH SEMESTER – NOVEMBER 2003
ST-5500/STA 505/S 515 – ESTIMATION THEORY
03.11.2003 Max:100 marks
1.00 – 4.00
SECTION-A
Answer ALL questions. (10×2=20 marks)
- State the problem of point estimation.
- Define ‘bias’ of an estimator in estimating a parametric function.
- Define a ‘Uniformly Minimum Variance Unbiased Estimator’ (UMVUE).
- Explain Cramer-Rao lower bound.
- Define completeness and bounded completeness.
- Examine if is complete.
- Let X1, X2 denote a random sample of size 2 from B(1, q), 0<q<1. Show that X1+3X2 is sufficient of q.
- Give an example where MLE is not unique.
- Define BLUE
- State Gauss – Markoff theorem.
SECTION-B
Answer any FIVE questions. (5×8=40 marks)
- Show that the sample variance is a biased estimator of the population variance. Suggest an UBE of .
- If Tn is asymptotically unbiased with variance approaching zero as n , show that Tn is consistent.
- Show that UMVUE is essentially unique.
- Show that the family of Binomial distributions is complete.
- State and establish Lehmann – Scheffe theorem.
- State and prove Chapman – Robbin’s inequality.
- Give an example where MLE is not consistent.
- Describe the linear model in the Gauss – Marboff set-up.
SECTION-C
Answer any TWO questions. (2×20=40 marks)
- a) Let X1, X2,….., Xn (n > 1) be a random sample of size n from P (q), q > 0. Show that the class of unbiased estimator of q is uncountable.
- b) Let X1, X2,….., Xn denote a random sample of size n from a distribution with pdf
f(x) ;q) =
0 , other wise.
Show that X(1) is a consistent estimator of q. (10+10)
- a) Obtain CRLB for estimating q, in the case of
f based on random sample of size n.
- b) State and establish factorization theorem in the discrete case. (8+12)
- a) Explain the method of maximum likelihood.
- b) Let X1, X2, …., Xn denote a random sample of size n from N (. Obtain MLE of q = (. (5+15)
- a) Let Y = Ab + e be the linear model where E (e) = 0. Show that a necessary and sufficient condition for the linear function of the parameters to be linearly estimable is that rank (A) = rank .
- b) Explain Bayesian estimation procedure with an example. (10+10)
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