fMaker: Create formulas from strings to be used in linear models

In c-langille/pStepwise: Variable selection for linear regression models based on p-values

Description

This function takes a string and a linear model and either adds the predictor to the model, or removes it.

Usage

fMaker(pred, fitCurrent, add = T)

Arguments

pred	the predictor to be added or removed from the current model
fitCurrent	the current model to be updated
add	by default adds the predictor to to the model. add=F removes the predictor from the model

Value

the updated model of type "lm"

See Also

pStepwise

Examples

#Using the leafshape data set from the DAAG package

#Adding a predictor to a linear model
data(leafshape)
attach(leafshape)
currentModel <- lm(bladelen~bladewid + latitude, data = leafshape)
newModel <- fMaker("petiole", currentModel)
newModel$call
#lm(formula = bladelen ~ bladewid + latitude + petiole, data = leafshape)

#Removing a predictor from a linear model
currentModel <- lm(bladelen~bladewid + latitude, data = leafshape)
newModel <- fMaker("latitude", currentModel, add = FALSE)
newModel$call
#lm(formula = bladelen ~ bladewid, data = leafshape)

c-langille/pStepwise documentation built on May 13, 2019, 9:55 a.m.