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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
