Page 132 - 006
P. 132

126




                            6/          Intercept  = -1.76963 (t = -14.12847, df = N £ k = 5, p<0.01)



                                                B  = Probit regression coefficient   6 &  &   %  (slope)
                                                = 0.22027 (t = 15.54499, df = N £ k = 5, p<0.01)



                                               N  =   (#   &
                                                = 7

                                                k = *        parameters estimated
                                                   1
                                                = 2 (&6  Intercept 
	# &   B)



                          (	  	7 &   ! .	 L,' /5( &6
                                         PROBIT  (p)    -    =  1.76963 +  0.22027(co nc.)

                                                                                     /
                                                                                 )



                                                         )


                     2    * 

  '(! #!    J         H+ &     
           '5(* 

  !  
 
#
                                                                                            2

                                                                           /

                                       +/
                           /

                       )

                       '5('   "     .#   5  &     
    
 '  !H   '  (# p<0.01 &   χ  = 23.223
                              1


                                    +7

                   ' / df = 5    3 * 
 Chi-square Analysis 5( (	                      '     ! !   #


                                                                                 )
                                                                                             1
                                                                                     /
                                                                  3
                     &   probit model

                     4        !       Probit model     
  &1      &  
    #!   & +/   +/

                     5       "H+ !  Q        DDVP ' /&            8.03383  ppm  '1         "3	
  "5(

                                    )
                   50%  +/ * 
&    ' /   &   Probit (p) &6 &   Z-score  +/ !    H&1    5(* 
 Probit model
                        7
                   (

                          
     &   LD
                                       50

                                                                PROBIT  (p)    -    =  1.76963 + 0.22027(co nc.)
                                                                          0 = -1.76963 +  0.22027(co nc.)
                          0.5
                                                                              1.76963
                                                                      conc. =
                                                                              0.22027
                                                                      conc. =  . 8  03383   ppm


                                         Z = 0
                                       Prob = 0.5
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