Page 133 - 006
P. 133

127





                          
     &  LD  10



                                                                PROBIT   (p)    -    =  1.76963 + 0.22027(co nc.)
                                                                     . 1 -  28155 = -1.76963 +  0.22027(co nc.)


                       0.1                                                    1.76963 - 1.28155
                                                                      conc. =
                                                                                   0.22027
                                                                      conc. =  . 2  2158   ppm



                                Z = -1.28155
                              Prob = 0.1





                          
     &  LD  90

                                                                PROBIT   (p)    -    =  1.76963 + 0.22027(co nc.)

                                                     0.9
                                                                     . 1 28155 = -1.76963 +  0.22027(co nc.)
                                                                              1.76963 + 1.28155
                                                                      conc. =
                                                                                   0.22027
                                                                      conc. =   . 13  852   ppm



                                                 Z = 1.28155
                                              Prob = 0.9



                                                           	/
                     6        &   . !	" (rage)   %   &    %6/    95%    &   8  /"' /'1   "5(   +/ &   8  /"*
                    ")        lower     upper





                     7        
  V&   !	 . L,      &           !  Q       DDVP 
	#&   Probit Z-
                   score  +/   
  
 !          
  x   &   Z-score = 0   6 ' /&   Probit (p) = 0.5
                   * 
*0( 	(  "	  
  x 
Y* 5( &  &           !  Q     ''1        5(  50% 5(  %
                                                                            /
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