Hi Jinsong, you can use the package drc on CRAN to fit logit and Weibull models (but not the probit model) with natural mortality/response and/or natural immunity to binomial data (maximum likelihood estimation).
To get an idea try: library(drc) ?earthworms Christian ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
