fitprobit function

Fit a Probit Regression to Dose-Effect Data

Fit a probit regression to dose-effect data, using the log10 of the dose as the response.

fitprobit(dat)

Arguments

• dat: A data frame of toxicity data, including at least three variables: dose (the concentration of the tested chemical), ntot (the number of individuals tested), and nfx (the number of affected individuals).

Returns

A an object of class glm.

Details

Only those rows with dose > 0, ntot > 0, and nfx >= 0

are used in fitting the model.

Examples

toxdat <- data.frame(
 dose=c(0.05, 0.0625, 0.125, 0.25, 0.5, 1),
  ntot=rep(8, 6),
  nfx = c(0, 1, 4, 4, 6, 8))
fitprobit(toxdat)