# Simple slopes analysis for Moderated regression

### 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.

### See Also

“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")
``` |