lOMoARcPSD|55995405
STA 303 Theory of estimation
Barchelor of information technology (South Eastern Kenya University)
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                                                      lOMoARcPSD|55995405
                 SOUTH EASTERN KENYA UNIVERSITY
  THIRD YEAR,SECOND SEMESTER EXAMINATION FOR THE DEGREE OF BACHELOR
                    OF SCIENCE IN ACTUARIAL SCIENCE
                       UNIVERSITY EXAMINATONS 2018/2019
                               STA 303: THEORY OF ESTIMATION
            DATE…..………………                                                         TIME 2 HOURS
                                INSTRUCTIONS TO CANDIDATES
                     Answer questionONE and any other TWO questions in this paper.
                                    QUESTION ONE (30 MARKS)
(a) Define the terms below as used in statistics.                                            (3 marks)
(i) Parameter
(ii) Statistic
(iii) An estimator
(b) State any three requirements of a good estimator.                                        (3marks)
(c) Proof that the sample mean is an unbiased estimator of population mean.                  (4marks)
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                                                       lOMoARcPSD|55995405
(d) Differentiate between parametric and non- parametric statistical test in statistics giving
    relevant examples.                                                                      (4 marks)
(e) Let x1,x2 …, xnbe random sample from a poison distribution with parameter λ. Find the
     estimator for λ, using any suitable method.                                            (5 marks)
(f) Proof that the sample mean square (S2) is an unbiased estimator of the population variance.
                                                    (4 marks)
(g) Explain the concept of UMVUE in estimation.                                            (4marks)
(h) Explain the meaning of the following terms:                                         (3 marks)
       (i)      Point estimation
       (ii)      Confidence interval
       (iii)    Interval estimation
                                    QUESTION TWO (20 marks)
       (a)     Using a suitable example proof the consistency requirement of a good point
               estimator.
                                                                                          (7marks)
       (b) Discuss the concept of jointly sufficient in statistics.                      (7 marks)
       (c) Discuss the concept of interval estimation using a relevant example.            (6 marks)
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                                                     lOMoARcPSD|55995405
                                     QUESTION THREE                        (20 marks)
(a)     Let x1,x2 …, xnbe a random sample from a Normal distribution. Find the maximum
        likelihood estimators of μ and σ            (10marks)
(b)      Let x1,x2 …, xn be random samples from uniform distribution in [ϴ - ½ , ϴ + ½] Find the
         maximum likelihood estimators of ϴ.                                      (10marks)
                                      QUESTION FOUR (20MARKS)
(a)     Explain the concept of factorization criterion in estimation.                     (10 marks)
(b)     Using relevant examples discuss the concept of least squares estimation. (10 marks)
                                       QUESTION FIVE (20 marks)
(a) Discuss the concept of sufficiency as used in estimation theory.                     (5 marks)
(b) Explain the Cramer-Rao inequality.                                                   (6 marks)
(c) Let x1,x2 …, xnbe random sample from apoisson distribution Show that;
      T= Max(x1, x2 ………xn) is a sufficient statistic for λ.                             (9 marks)
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