simple_slopes: Simple Slopes Analysis

In AlexChristensen/simpleRslopes: Simply Simple Slopes for R

Description

Computes simple slopes for objects fit with the class "lm"

Usage

simple_slopes(
  fit,
  variable1name,
  variable1values = NULL,
  variable2name,
  variable2values = NULL,
  plot_slopes = TRUE
)

Arguments

fit	"lm" object. Object from a model fit using a regression model
variable1name	Character. Name of the first variable in interaction from fit
variable1values	Numeric. Values to be used when first variable is the moderator. If variable1type = "dichotomous", then defaults to values 0 and 1. If variable1type = "continuous", then defaults to values -1 SD, M, and +1 SD
variable2name	Character. Name of the second variable in interaction from fit
variable2values	Numeric. Values to be used when second variable is the moderator. If variable2type = "dichotomous", then defaults to values 0 and 1. If variable2type = "continuous", then defaults to values -1 SD, M, and +1 SD
plot_slopes	Boolean. Should simple slopes be plotted? Defaults to TRUE

Value

Returns a list containing:

fit	Returns fit object back
results	Data frame with variable, moderator, values of moderator betas of simple slopes, t values, p-values, and significance level
parameters	A list containing degrees of freedom (df), betas (from fit), interaction name, variance-covariance matrix of the variables involved, and data from fit
plot_args	Internal use only. Arguments for plots

Author(s)

Alexander Christensen <[e-mail]>

References

Preacher, K. J., Curran, P. J., & Bauer, D. J. (2006). Computational tools for probing interactions in multiple linear regression, multilevel modeling, and latent curve analysis. Journal of Educational and Behavioral Statistics, 31(4), 437-448.

Examples

# Generate data
df <- data.frame(
  y = rnorm(100),
  x1 = rnorm(100),
  x2 = rnorm(100)
)

# Estimate linear model
fit <- lm(y ~ x1 * x2, data = df)

# Estimate simple slopes
simple_slopes(
  fit = fit,
  variable1name = "x1", # must be name as it appears in 'fit' object
  variable2name = "x2", # must be name as it appears in 'fit' object
  plot = TRUE
)

AlexChristensen/simpleRslopes documentation built on Feb. 6, 2022, 12:32 a.m.