Question

I run a nonparametric regression using the np package (npreg) and try to plot my results for the variable of interest x1 holding all other variables at their means/modes.

library("np")

y  <- rnorm(100)
x1 <- rnorm(100,10,30)
x2 <- rbinom(100,1,0.5)
x3 <- rbinom(100,1,0.5)

model.np <- npreg(y ~ x1 + x2 + x3)
plot(model.np)

The plots are exactly what I want but I cannot figure out how to generate them separately “by hand”. In particular, I only want the first (of the three) output plots.

Answer 1

Apparantly, a detailed answer can be found in the help file for the npplot-routine with plot.behavior being the crucial argument.

For my example, plotting only the x1-graph could be done via:

nlmodel.plot <- plot(model.np, plot.behavior="data")

y.eval <- fitted(nlmodel.plot$r1) #fit partial regression model for r1=airnoise
y.se <- se(nlmodel.plot$r1) #grab SE from botstrap 
y.lower.ci <- y.eval + logp.se[,1] #lower CI
y.upper.ci <- y.eval + logp.se[,2] #upper CI

x1.eval <- nlmodel.plot$r1$eval[,1]  #grab x1 values saved in plot$r1

plot(x1,y)
 lines(x1.eval,y.eval)
 lines(x1.eval,y.lower.ci,lty=3)
 lines(x1.eval,y.upper.ci,lty=3)