coefprobit: Calculate the Coefficients of a Probit Regression Fit

In LW1949: An Automated Approach to Evaluating Dose-Effect Experiments Following Litchfield and Wilcoxon (1949)

Description

Calculate the coefficients from a fitted probit regression model with confidence intervals.

Usage

coefprobit(pfit, alpha = 0.05)

Arguments

pfit	An object of class glm representing a probit regression fit to dose-effect data, typically the result of a call to fitprobit. Dose should be the only independent variable in the model.
alpha	A numeric scalar, the significance level used to generate 100*(1 - alpha)% confidence limits, default 0.05.

Value

A numeric vector of length six, the intercept and slope of the dose-response curve, each with 100*(1 - alpha)% confidence limits.

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))
myfit <- fitprobit(toxdat)
coefprobit(myfit)

Example output

Warning message:
no DISPLAY variable so Tk is not available 
      int    ilower    iupper     slope    slower    supper 
1.7056891 0.7830307 2.6283475 2.4427954 1.3347284 3.5508624 

LW1949 documentation built on May 2, 2019, 6:11 a.m.