Creating a scatter diagram with least square regression line according to Type

Question

I have data that is set up like the following:

type     age     rust
0        1       29.00
0        0       95.00
.....

1        1800    7.56

I would like to create a scatter diagram of rust vs. age according to Type 0 and 1. I also would like to overlay a least square regression line in red for type 0 and blue for type 1.

I tried the following but when I tried overlaying the abline command it was way off the graph:

library(lattice)

xyplot(rust$rust~rust$age, group = rust$type, main = "Scatterplot of Rust vs. Age by Type")
abline(rust$rust~rust$age, col = "blue")

Answer 1

Elaborating on my comment, with your specific data, something like this should work.

require(lattice)

set.seed(42)
type <- rep(c(0,1),20)
age <- sample(1:100, 40, replace=TRUE)
rust <- type*5 + 0.3 * age + rnorm(40)

df <- data.frame(type = type, age = age, rust = rust)


myPanel <- function(x,y,...) {
  panel.xyplot(x,y,...)
  panel.abline(lm(y~x), ...)
}

xyplot(rust ~ age, group = type, data = df, panel = panel.superpose,
       panel.groups = myPanel)