sim.slopes {QuantPsyc}R Documentation

Moderated Simple Slopes

Description

Computes the simple slopes for a moderated regression model.

Usage

sim.slopes(mod, z, zsd = 1, mcz = FALSE)

Arguments

mod linear model - usually constructed with moderate.lm
z moderating variable
zsd Multiple for SD of z; number of SDs from mean to construct simple slopes
mcz logical whether z is already centered or not in the original data

Details

Constructs the simple slopes for arbitrary values of z (e.g., +/- 1, 2, 3 standard deviations) involved in a moderated multiple regression equation.

Value

A table with the following values for zHigh (Meanz + zsd*SDz), Mean(Meanz), and zLow (Meanz - zsd*SDz):

INT Intercept of simple slope
Slope Slope of the simple slope
SE Standard Error of the slope
LCL, UCL Lower and Upper confidence limits for slope

Author(s)

Thomas D. Fletcher tom.fletcher.mp7e@statefarm.com

References

Aiken, L. S., & West, S. G. (1991). Multiple regression: Testing and interpreting interactions. Newbury Park: Sage Publications.

Cohen, J., Cohen, P., West, S. G., & Aiken, L. S. (2003). Applied multiple regression/correlation analysis for the behavioral sciences, 3rd ed. Mahwah, NJ: Lawrence Erlbaum Associates.

See Also

moderate.lm, graph.mod

Examples


data(tra)
lm.mod1 <- moderate.lm(beliefs, values, attitudes, tra)
ss.mod1 <- sim.slopes(lm.mod1, tra$values)
ss.mod1


[Package QuantPsyc version 1.3 Index]