Plotting curves in lattice panels
On 9/18/08, David Scott <d.scott at auckland.ac.nz> wrote:
I have a data set concerning ferritin levels in blood. There are three
relevant columns for this question, ferritin (continuous), score (ordered,
from 0 to 8) and gender. There is a good linear relationship between
log(ferritin) and score for each gender.
I can create a lattice plot on the log scale showing the data and the
fitted line:
xyplot(log(ferritin) ~ total|gender, data = blood,
panel = function(x, y, ...){
panel.xyplot(x, y)
panel.abline(lm(y ~ x), type = 'l', ...)
}
)
I would like to be able to plot the data and the fitted line on the
original scale however. I can't see how to do that.
Something like this should work:
xyplot(ferritin ~ total|gender, data = blood,
panel = function(x, y, ...){
panel.xyplot(x, y)
fm <- lm(log(y) ~ x)
panel.curve(exp(predict(fm, newdata = list(x = x))))
})
-Deepayan