plotAncova: Creates plots for one way ANCOVAs

Description

ANCOVA plots are created, potentially with distinct line types and/or symbols and colors for treatments. A legend relating ciphers to treatments is also included.

Usage

plotAncova(model, pch = NULL, lty = NULL, col = NULL, leg.loc = "topright", 
leg.cex = 1, leg.bty = "o", leg.bg = par("bg"), legend.title = NULL,...)

Value

Returns an ANCOVA plot and model coefficients. Slopes and intercepts for factor level lines are also stored as invisible output (see Examples).

Arguments

model: Result from lm. An additive model results in a common slope plot. An interaction model results in distinct slopes for treatments
pch: A scalar, or a vector of length n defining symbols for treatments.
lty: A scalar, or a vector of length n defining line types for treatments.
col: A scalar, or a vector of length n defining color for symbols and lines.
leg.loc: Location of the legend. "n" suppresses the legend.
leg.cex: Character expansion from legend.
leg.bty: Box type from legend.
leg.bg: Background color from legend.
legend.title: Legend title from legend.
...: Additional arguments from plot

Author

Ken Aho

Examples

Run this code


x <- rnorm(20)
y <- 3 * x + rnorm(20)
cat <- c(rep("A",5),rep("B",5),rep("C",5),rep("D",5))
l <- lm(y ~ x * cat)
plotAncova(l, leg.loc = "bottomright")

# Access intercepts and slopes
pa <- plotAncova(l)
pa