Putting data set results in a graph
Below is a worked example of putting data set results in a graph. The data set I used is automobile dataset:

The commands I used in a do-file are:
clear all
sysuse auto
quiet: summarize mpg
twoway ///
scatter mpg rep78, ///
text(40 3 "The mean mpg is:`=string(`=r(mean)',"%8.2f")'", placement(right)) ///
text(38 3 "The sd mpg is: `=string(`=r(sd)',"%8.2f")'" , placement(right))
exit
You may find more useful information in the book Speaking Stata Graphics