drc (version 0.9-0)

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, ..., test = NULL)

anova.drclist(object, ..., test = NULL)

Arguments

object

an object of class 'drc'.

...

additional arguments.

test

a character string specifying the test statistic to be applied. Use "od" to assess overdispersion for binomial data.

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, that is: one model is a submodel of the other model.)

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 = w4())
anova(model1)   

## Comparing a Gompertz three- and four-parameter models using an F test
model2 <- multdrc(FA, fct = w3())
anova(model2, model1)  # reduction to 'w3' not possible (highly significant)   


rm(model1, model2)