modreg: moderated regression

In zakarydraper/modreg: Functions for Exploring Interactions in Moderated Multiple Regression

Description

moderated regression

Usage

modreg(dv, idv, mod1,
            mod2 = NULL, multMOD1 = 1, multMOD2 = 1, ci = 95,
            xlab = NULL, ylab = NULL)

Arguments

dv	A numeric vector representing the dependent/outcome variable.
idv	A numeric vector representing participant scores on the independent/predictor variable.
mod1	Either a numeric vector (for continuous moderators) or factor (for categorical moderators) representing the first moderator. Note: currently only numeric values are accepted.
mod2	An optional numeric vector or factor representing the second moderator. Note: this option is not currently available.
multMOD1	The number of SD above and below the mean of the first moderator variable, for which simple slope statistics will be calculated.
multMOD2	The number of SD above and below the mean of the second moderator variable, for which simple slope statistics will be calculated.
ci	The confidence level to be calculated. Default is 95.
xlab	The x-axis label for the simple slope plot.
ylab	The y-axis label for the simple slope plot.

Value

A list with the following elements:

lm	The significance test for the multiple regression equation.
beta	The raw and standardized beta weights for the full equation.
slopes	The intercepts and raw (unstandardized) simple slope coefficients for the DV on the IDV at three levels of the moderator.
std_slopes	The standardized simple slopes (beta, SE, and 95% confidence intervals).
slope_dv	The score on the moderator for which the simple slope for the DV on the IDV is zero (flat).
reg_lines	The score on the independent variable for which the simple regression lines for mod = high and mod = low intersect.

Author(s)

Zakary A. Draper & Brian P. O'Connor

Examples

# Is the relationship between automobile horsepower and fuel economy moderated by 1/4 mile time?
data(mtcars)
attach(mtcars)
modreg(hp, mpg, qsec)

zakarydraper/modreg documentation built on May 8, 2019, 1:23 p.m.