# simpleSlope: Simple slopes analysis for Moderated regression In pequod: Moderated Regression Package

## Description

Simple slope analysis according to Cohen, Cohen, West, & Aiken (2003); Bauer & Curran, (2005); and Dawson and Richter (2006) approaches.

## Usage

 ```1 2 3``` ```simpleSlope(object, pred, mod1, mod2, coded, ...) ## Default S3 method: simpleSlope(object, pred, mod1, mod2="none",coded = "none", ...) ```

## Arguments

 `object` an object of class "lmres": a moderated regression function. `pred` name of the predictor variable `mod1` name of the first moderator variable `mod2` name of the second moderator variable. Default "none" is used in order to analyzing two way interaction, `coded` a character vector of coded variables `...`

## Details

Simple slope analysis for moderated regression. If two way interaction is analyzed, the function computes simple slope analysis and region of significance( Bauer & Curran, 2005). If three way interaction is analyzed, the function compute simple slope analysis and difference slope test (Dawson and Richter, 2006).

## Value

simpleSlope returns an object of class "simpleSlope".

An object of class "simpleSlope" is a list containing at least the following components:

 `nomY` the name of dependent variable `orde` it's 2 for two way interaction, it's 3 for three way interaction `points` Estimated points of dependent variable as a function of levels of moderators and predictor `simple_slope` a matrix summarizing simple slopes results `delta_slope` (only for three way interaction)a matrix summarizing difference slope tests `Df` degree of freedom `conf95` (only for two way interaction)confidence interval of moderator region of significance

## Author(s)

Alberto Mirisola and Luciano Seta

## References

-Bauer, D. J., & Curran, P. J. (2005). Probing Interactions in Fixed and Multilevel Regression: Inferential and Graphical Techniques. Multivariate Behavioral Research, 40(3), 373-400. -Cohen, J., Cohen, P.,West, S. G.,& Aiken, L. S. (2003). Applied multiple regression/correlation analyses for the behavioral sciences (3rd ed.). Mahwah, NJ: Lawerence Erlbaum Associates, Inc. - Dawson, J. F., and Richter, W. (2006) Probing Three-Way interactions in moderated multiple regression: Development and application of a slope difference test. Journal of Applied Psychology, 4, 917-926.

“summary.simpleSlope”

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12``` ``` ## simple slope for three way interaction library(car) data(Highway1) model3<-lmres(rate~len*trks*sigs1, centered=c("len","trks","sigs1"),data=Highway1) S_slopes<-simpleSlope(model3,pred="len",mod1="trks", mod2="sigs1") ## The function is currently defined as function (object, pred, mod1, mod2, coded, ...) UseMethod("simpleSlope") ```

### Example output

```Loading required package: ggplot2