I am learning logistic regression modeling from the book Applied Logistic Regression by Hosmer.
I need to create a plot named "create univariable smoothed scatterplot on logit scale", something like this one (Figure 4.2 page 107):
Can anyone help? Thanks.
Thanks for all the answers. I tried creating the plot, and discover that
smooth.spline created the graph by using percentage (
nrow((df[df[,"dfree"]==1,]))/nrow(df)), rather than logit (
log(nrow(df[df[,"dfree"]==1,])/nrow(df[df[,"dfree"]==0,]))) when creating the y-axis. Yes, the graph looks similar, but I wonder if we can create an exact copy of that? Thanks.
One more thing, when using logit, some of the logit value in the data.frame is
Inf, which is not allowed in
I have further question concerning my edit:
What if I manually dropped all
-Inf in my data.frame and do
smooth.spline on that data.frame? Is it appropriate?