Page 16 - Contributed Paper Session (CPS) - Volume 3
P. 16

CPS1923 Deemat C M. et al.
                  Corollary  3.2.  Let    be  continuous  non-negative  random  variable  with
                                       ∗
                             
                           −
                   () =   then the distribution of  √(∆ − ∆ ( )), as   →  ∞, is Gaussian
                                                          ̂ ∗
                                                                ∗
                                                                    ∗
                   ∗
                  ̅
                             
                                                    1
                                                2
                  with mean zero and variance  =  12  .
                                                0
                  Apart from the exact test we can construct an asymptotic test based on the
                  asymptotic distribution of ∆ . Hence in case of the asymptotic test, for large
                                            ̂ ∗
                  values  of ,  we  reject  the  null  hypothesis  in  favour  of  the  alternative
                                                               0
                  hypothesis  , if
                               1
                                                √12(∆ ) >  ,
                                                      ̂ ∗
                                                             ∝
                  where  , is the upper a-percentile of (0, 1).
                          ∝

                  3.2.  Pitman’s  asymptotic  efficacy.  In  our  case,  the  Pitman’s  asymptotic
                  efficacy (PAE) is given by
                                      
                                              ∗
                                          ∗
                                     |   ∆  ( )|  →  0
                                                                  ′
                                                                                  ∗′
                               ∗
                            ∗
                      (∆ ( )) =              = √12(  ( ) −  ( )  ( )),
                                              0                    0         0    
                  where   =  (( ,  )) and   is  the  mean  of   under  the  alternative
                                           ∗
                                       ∗
                                                    ∗
                                                                      ∗
                                       1
                                          2
                                                    
                  hypothesis and the prime denotes the differentiation with respect to . We
                  calculate the PAE value for three commonly used alternatives which are the
                  members of RIMRL   shock  class
                      Next we compare the performance of the proposed test with some other
                  tests available in the context of age replace model. The Table 2 gives the PAE
                  values for different test procedures. From the Table 2, it is clear that our test
                  is quite efficient for the Weibull and linear failure rate alternatives.

                                   Table 2. Pitman's asymptotic efficacy (PAE)
                          Distribution   Proposed test   Li and Xu (2008)   Kayid et al. (2013)
                              Weibull            1.2005           1.1215              0.4822
                     Linear failure rate         0.8660           0.5032              0.4564
                            Makeham              0.2828           0.2414               2.084

                                    Table 3. Empirical type 1 error of the test
                                 Type 1 Error (5% level)    Type 1 Error (1% level)
                           10             0.0635                     0.0123
                           20             0.0540                     0.0115
                           30             0.0518                     0.0107
                           60             0.0516                     0.0102
                           80             0.0511                     0.0100
                           100            0.0504                     0.0101

                  4.   Simulation and data analysis
                      Next, we report a simulation study for evaluating the performance of our
                  asymptotic test against various alternatives. The simulation was done using R
                  program. Finally, we illustrate our test procedure using a real data.


                                                                       5 | I S I   W S C   2 0 1 9
   11   12   13   14   15   16   17   18   19   20   21