Page 21 - Contributed Paper Session (CPS) - Volume 8
P. 21

CPS2151 Sarah B. Balagbis
                 a.  Choose m observations as “close” to each other as possible. This is
                    accomplished by fitting the model  =  +   +   +.. for all
                                                                  1 1
                                                              0
                                                                          2 2
                                                        
                    observations  and  choosing  m  observations  with  the  smallest
                    residuals.
                                                                                    1
                 b.  Using  the  m  observations  from  step  (a),  fit  the  model  =  +
                                                                              
                                                                                    0
                      1
                               1
                       +    + … and store the parameter estimates. Compute the
                               2 2
                      1 1
                    residuals  of  the  remaining  (n-m)  observations  and  choose  one
                    observation  with  the  smallest  residual  to  be  added  to  the  m
                    observations in step (a). This yield (m+1) observations.
                 c.  Using the (m+1) observations from step (b), fit the model again and
                    store the parameter estimates. Compute the residual of the remaining
                    [n  –  (m+1)]  observations  and  choose  one  observation  with  the
                    smallest residual.
                 d.  Continue  the  process  of  estimating  the  parameters  while  Cook’s
                    distance for the newly entered observation is less than ε, otherwise
                    stop the process and get the series of parameter estimates you have
                    stored.
             2.   For  each  of  the  series  of  parameter  estimates,  compute  a  bootstrap
                 estimate:
                 a.   Draw  a  simple  random  sample  of  size  n  with  replacement.
                                                 
                                              1
                                                   ̂
                                        ̂ ()
                 b.    Compute the mean.    =  ∑ 
                                                    
                                              
                                                =1
                 c.    Repeat (a) and (b) B times, where B is large.
                                                            
                                                         1
                                                               ̂ ()
                 d.     Compute the bootstrap estimat  ̂   =    ∑   , and the standard
                                                           =1
                                                     1/2
                                   1
                                                  ̂
                                                      2
                     error ̂   = [  − 1 ∑( ̂ ()  −  ) ]
                                                   
                                       =1
             3.  Given the bootstrap estimates of the parameters do the following:
                                                       ̂
                                         ̂
                                              ̂
                  a.  Compute  =  −  −    −    − ⋯
                                                       2 2
                                          0
                               
                                     
                                               1 1
                  b.  For each i = 1, 2, …N, fit the model  =  (−1) +   and store the
                                                                         
                                                         
                     parameter estimates as  , i = 1,…, N.
                                             
                  c.  Compute the bootstrap estimate ̂  by following step 2 above.
                                                      
                                      1
             4.  Generate new series  =  − ̂ (−1) and iterate from step 1. Continue
                                           
                                      
                 the  iteration  until  there  is  no  substantial  change  in  the  values  of  the
                 parameter estimates
            Simulation Studies
                A simulation study is performed to illustrate and evaluate the performance
            of the proposed estimation procedure. Seventy (70) panel points and eighty
                                                                10 | I S I   W S C   2 0 1 9
   16   17   18   19   20   21   22   23   24   25   26