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.
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")