Page 261 - Schaum's Outlines - Probability, Random Variables And Random Processes
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ESTIMATION  THEORY                           [CHAP  7



                   The likelihood function is given by  [Eq. (2.40)]




                Thus,


                where


                and
                Setting d[ln L(A)]/dA = 0, the maximum-likelihood estimate A,,   of 1 is obtained as

                                                  A,,   = -  xi
                                                        n i=l
                Hence, the maximum-likelihood estimator of A is given by






          7.9.   Let  (XI, . . . , X,)  be  a  random  sample of an  exponential  r.v.  X  with  unknown  parameter  A.
                Determine the maximum-likelihood estimator of 1.
                   The likelihood function is given by [Eq. (2.48)]





                Thus,

                and

                Setting d[ln  L(R)]/dl = 0, the maximum-likelihood estimate i,, of 1 is obtained as





                Hence, the maximum-likelihood estimator of 1 is given by







          7.10.  Let (XI, . . . , X,)  be  a random sample of  a normal  random  r.v. X with  unknown  mean  p and
                unknown variance a2. Determine the maximum-likelihood estimators of p and a2.

                   The likelihood function is given by  [Eq. (2.52)]
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