addLines {rockchalk}

Superimpose regression lines on a plotted plane

Description

The examples will demonstrate the intended usage.

Usage

addLines(to = NULL, from = NULL, col, lwd = 2, lty = 1)

Arguments

to

a 3d plot object produced by plotPlane

from

output from a plotSlopes or plotCurves function (class="rockchalk")

col

color of plotted lines (default: "red")

lwd

line width of added lines (default: 2)

lty

line type of added lines (default: 1)

Details

From an educational stand point, the objective is to assist with the student's conceptualization of the two and three dimensional regression relationships.

Value

NULL, nothing, nicht, nada.

Author(s)

Paul E. Johnson [e-mail]

Examples

##library(rockchalk)


set.seed(12345)

dfadd <- genCorrelatedData2(100, means = c(0,0,0,0), sds = 1, rho = 0,
       beta = c(0.03, 0.01, 0.1, 0.4, -0.1), stde = 2)

dfadd$xcat1 <- gl(2,50, labels=c("M","F"))

dfadd$xcat2 <- cut(rnorm(100), breaks=c(-Inf, 0, 0.4, 0.9, 1, Inf),
                   labels=c("R", "M", "D", "P", "G"))

dfadd$y2 <- 0.03 + 0.1*dfadd$x1 + 0.1*dfadd$x2 +
    0.25*dfadd$x1*dfadd$x2 + 0.4*dfadd$x3 - 0.1*dfadd$x4 +
    0.2 * as.numeric(dfadd$xcat1) +
    contrasts(dfadd$xcat2)[as.numeric(dfadd$xcat2), ] %*% c(-0.1, 0.1, 0.2, 0) +
    1 * rnorm(100)

summarize(dfadd)

## linear ordinary regression
m1 <- lm(y ~ x1 + x2 + x3 + x4, data = dfadd)
summary(m1)

mcDiagnose(m1)

## These will be parallel lines

plotSlopes(m1, plotx = "x1", modx = "x2", modxVals = "std.dev.",
           n = 5, main = "A plotSlopes result with \"std.dev.\" values of modx")


m1ps <- plotSlopes(m1, plotx = "x1", modx = "x2", modxVals = c(-2,0,2))

m1pp <- plotPlane(m1, plotx1 = "x1", plotx2 = "x2",
                  ticktype = "detailed", npp = 10)

addLines(from = m1ps, to = m1pp, lty = 1, lwd = 2)

m1pp <- plotPlane(m1, plotx1 = "x1", plotx2 = "x2", ticktype = "detailed",
                  npp = 10)
addLines(from = m1ps, to = m1pp, lty = 2, lwd = 5, col = "green")

## Other approach would wrap same into the linesFrom argument in plotPlane

plotPlane(m1, plotx1 = "x1", plotx2 = "x2", ticktype = "detailed",
          npp = 10, linesFrom = m1ps)

## Need to think more on whether dotted lines from ps object should
## be converted to solid lines in plotPlane.