drc (version 0.8-2)

anova.drc: ANOVA for non-linear model fits

Description

'anova' produces an analysis of variance table for one or two non-linear model fits.

Usage

anova.drc(object, ...)

anova.drclist(object, ..., test="F")

Arguments

object

an object of class 'drc'.

...

additional arguments.

test

a character string specifying the test statistic to be applied. If not equal to '"F"' (F-test), a likelihood ratio test is used.

Value

• An object of class 'anova'.

Details

Specifying only a single object gives a test for lack-of-fit, comparing the non-linear regression model to a more general one-way or two-way ANOVA model. If two objects are specified a test for reduction from the larger to the smaller model is given. (This only makes statistical sense if the models are nested.)

References

Bates, D. M. and Watts, D. G. (1988) Nonlinear Regression Analysis and Its Applications, New York: Wiley & Sons (pp. 103--104).

See Also

The function anova.lm for linear models.

Examples

## Comparing the nonlinear model to a one-way ANOVA model using an F test
model1 <- multdrc(FA, fct=g4())
anova(model1)   

## Comparing a Gompertz three- and four-parameter models using an F test
model2 <- multdrc(FA, fct=g3())
anova(model2, model1)  # reduction to g3() not possible (highly significant)   

rm(model1, model2)