drc (version 1.3-0)

hormesis: Hormesis data set

Description

Results from an experiment with isobutylalcohol in nutrient solution.

Usage

data(hormesis)

source

van Ewijk, P. H. and Hoekstra, J. A. (1993) Calculation of the EC50 and its Confidence Interval When Subtoxic Stimulus Is Present, ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY, 25, 25--32.

Details

The data set illustrates hormesis, presence of a subtoxic stimulus.

References

van Ewijk, P. H. and Hoekstra, J. A. (1994) Curvature Measures and Confidence Intervals for the Linear Logistic Model, Appl. Statist., 43, 477--487.

Examples

## Look at data
head(hormesis)

## Monotonous dose-response model
hm.m1 <- drm(weight~conc, data=hormesis, fct=LL.3())

plot(hm.m1)

## Model fit in van Ewijk and Hoekstra (1994)
hm.m2 <- drm(weight~conc, data=hormesis, fct=BC.4())

plot(hm.m2, type = "fit", add = TRUE, lty = 2)

## Hormesis effect only slightly significant
summary(hm.m2)

## Hormesis effect highly significant
anova(hm.m1,hm.m2)