The five-parameter logistic function
read in the paramters and the independent variable value(s), and then return the 5pl function value(s). For the 4pl model, set g to be 1.
f5pl(pars, x)
pars |
numeric the parameters of the 5pl (or 4pl). It has the following content: [a, d, xmid, scal, g]. |
x |
numeric the log-transformed x value(s). |
The function has the following form
f(x)=a+(d-a)/((1+exp((xmid-x)/scal))^g)
the 5pl function value(s).
Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.