sim.slopes: Moderated Simple Slopes

In QuantPsyc: Quantitative Psychology Tools

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 [e-mail]

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

QuantPsyc documentation built on June 4, 2022, 1:06 a.m.