binomTools (version 1.0-1)

empLogit: Calculates the empirical logit transform

Description

The empirical logit transform allows for a tolerence such that infinity is not returned when the argument is zero or one.

Usage

empLogit(x, eps = 1e-3)

Arguments

x

numerical vector for which the empirical logit transform is desired

eps

numerical scalar; a tolerence to prevent infinite values

Value

the empirical logit transform of x

Examples

## The function is currently defined as
## function (x, eps = 1e-3) log((eps + x)/(1 - x + eps))

## Lifted from example(predict.glm):
ldose <- rep(0:5, 2)
numdead <- c(1, 4, 9, 13, 18, 20, 0, 2, 6, 10, 12, 16)
sex <- factor(rep(c("M", "F"), c(6, 6)))
SF <- cbind(numdead, numalive=20-numdead)
## budworm.lg <- glm(SF ~ sex*ldose, family=binomial)
## summary(budworm.lg)

empLogit(numdead/20)

## Possible usage:
## Explorative interaction plot:
interaction.plot(ldose, sex, empLogit(numdead/20))