LW1949 (version 1.1.0)

estimable: Determine if a Dose-Effect Relation is Estimable

Description

Determine if a dose-effect relation is estimable based on available data.

Usage

estimable(DEdata)

Arguments

DEdata

A data frame of dose-effect data (typically, the output from dataprep) containing at least two variables: dose, a numeric vector of chemical concentrations, and pfx, a numeric vector of proportional effects at each dose (see Details).

Value

A logical scalar indicating if a dose-effect relation is estimable.

Details

A dose-effect relation is defined to be estimable if and only if there are at least two test records and there is some (non-zero) variability in both the doses and the proportional effects. The input data are expected to be summarized by dose. If duplicate doses are provided, an error will be thrown.

Examples

conc <- c(0.0625, 0.125, 0.25, 0.5, 1)
numtested <- rep(8, 5)
nalive <- c(1, 4, 4, 7, 8)
mydat <- dataprep(dose=conc, ntot=numtested, nfx=nalive)
estimable(mydat)
nalive2 <- rep(4, 5)
mydat2 <- dataprep(dose=conc, ntot=numtested, nfx=nalive2)
estimable(mydat2)