abc {lamme}

the ABC procedure for model selection

Description

the AIC comparison with Modified Box-Cox Transformation (ABC) is a diagnostic procedure to help select among various additive and multiplicative models

Usage

abc(y, g, x = 0)

Arguments

y

the raw posttest scores of a continuous outcome variable.

g

the categorical variable that denotes the group membership.

x

(optional) the raw pretest scores of a continuous outcome variable.

Details

When only 'y' and 'g' are specified, the ABC procedure compares LANOVA and ANOVA models. When 'x' is also specified, the ABC procedure compares LANCOVA, ANCOVA, ANCOHET, and ANCOVA with log-transformed y.

Value

AIC results of different models. The model with smallest AIC is preferred.

Examples

data("schoene")
attach(schoene)
abc(post_HRT,group,pre_HRT)
abc(post_HRT,group)