l5 {drc} | R Documentation |
'l5' provides the five-parameter logistic function, self starter function and names of the parameters.
l5(fixed = c(NA, NA, NA, NA, NA), names = c("b", "c", "d", "e", "f"), useDer = FALSE)
fixed |
numeric vector. Specifies which parameters are fixed and at what value they are fixed. NAs for parameter that are not fixed. |
names |
a vector of character strings giving the names of the parameters. The default is reasonable. |
useDer |
logical. If TRUE derivatives are supplied, otherwise they are not supplied. Not implemented! |
The five-parameter logistic function is given by the expression
f(x) = c + frac{d-c}{(1+exp(b(log(x)-log(e))))^f}
The function is asymmetric for f different from 1.
See logistic
.
This function is for use with the function multdrc
.
Christian Ritz
Finney, D. J. (1979) Bioassay and the Practise of Statistical Inference, Int. Statist. Rev., 47, 1–12.
Related functions are l4
and l3
.
model1 <- multdrc(FA, fct=l5()) summary(model1) rm(model1)