ecotoxicology (version 1.0.1)

ProbitWeightingCoef: Calculate the weighting coefficient

Description

Returns the weighting coefficient

Usage

ProbitWeightingCoef(Z, Q, P, C)

Arguments

Z

numeric, ordinate to the normal distribution corresponding to the probability P

Q

numeric, 1-P

P

numeric, Probability P of expected probit

C

numeric, proportion of natural mortality

Value

the weighting coefficient

References

Finney D. J., 1964 Probit analysis: a statistical treatment of the sigmoid response curve. Cambridge University Press. Formula 6.3.

Examples

# Example from page 90 of Finney 1964:
# expected probit Y = 6.2, control mortality C = 59%
Y <- 6.2
C <- 0.59
P <- pnorm(Y-5)
Q <- 1-P
Z <- ProbitZ(Y)
# weighting coefficient = 0.141
ProbitWeightingCoef(Z,Q,P,C)