Plot the observed and fitted values from a linear regression using xyplot() from the lattice package

Question

I can create simple graphs. I would like to have observed and predicted values (from a linear regression) on the same graph. I am plotting say Yvariable vs Xv

Answer 1

Another option is to use panel.lmlineq from latticeExtra.

library(latticeExtra)
set.seed(0)
xsim <- rnorm(50, mean = 3)
ysim <- (0 + 2 * xsim) * (1 + rnorm(50, sd = 0.3))

## basic use as a panel function
xyplot(ysim ~ xsim, panel = function(x, y, ...) {
  panel.xyplot(x, y, ...)
  panel.lmlineq(x, y, adj = c(1,0), lty = 1,xol.text='red',
                col.line = "blue", digits = 1,r.squared =TRUE)
})