meLL: The log-logistic function

In DoseResponse/medrc: Mixed effect dose-response curves

Description

'meLL.X' provides the X-parameter log-logistic function.

Usage

meLL.2(x, b, e)

meLL.3(x, b, d, e)

meLL.4(x, b, c, d, e)

meLL.5(x, b, c, d, e, f)

Arguments

x	numeric dose vector.
b	steepness
e	ED50
d	upper limit
c	lower limit
f	asymmetry

Details

The five-parameter logistic function is given by the expression

f(x) = c + \frac{d-c}{(1+\exp(b(\log(x)-\log(e))))^f}

or in another parameterisation

f(x) = c + \frac{d-c}{(1+\exp(b(\log(x)-e)))^f}

The function is asymmetric for f different from 1.

References

Finney, D. J. (1979) Bioassay and the Practise of Statistical Inference, Int. Statist. Rev., 47, 1–12.

DoseResponse/medrc documentation built on May 28, 2019, 12:36 p.m.