form.interaction: Create interaction terms of predictor(s) and potential...

In mma: Multiple Mediation Analysis

Create interaction terms of predictor(s) and potential moderator(s).

Description

Create interaction terms of predictor(S) and potential moderator(s). Mainly for linear models.

Usage

form.interaction(x,pred,inter.cov,predref=NULL,kx=NULL)

Arguments

x	As the x in data.org.
pred	The predictor(s) that might have interaction effect with the potential moderators.
inter.cov	The vector of names of potential moderators, which are included in x as covariates.
predref	The reference group of the predictor if the predictor is categorical.
kx	The interaction is with the kx-th predictor(s). kx can be a vector. If kx is null, the interaction is with each predictor.

Details

form.interaction is used to create interaction terms between predictor(s) and potential moderator(s). The created interaction terms should be used as covariates in linear mediation analysis. The function is not needed for nonlinear mediation method.

Value

Return a matrix with the interaction terms pred*inter.cov.

Author(s)

Qingzhao Yu [e-mail]

See Also

"test.moderation", "moderate"

Examples

data("weight_behavior")
pred=data.frame(weight_behavior[,3])
names(pred)="pred"
x=weight_behavior[,c(2,4:14)]
inter=form.interaction(x,pred,inter.cov=c("sports","sweat"),predref=NULL) 
x=cbind(x,inter)
head(x)

mma documentation built on Aug. 30, 2023, 1:08 a.m.