This site provides several example regression codes in a number of different programming languages. To make learning regression more interesting, the codes make use of the charge form factor data found in Table I of L.N.Hand, D.G.Miller and R.Wilson, Rev. of Mod. Phys. 35 (1963) 342 to make proton radius extractions.

• EXCEL - using a spreadsheet allows one to see how the minimization works
• GNUPLOT - a powerful tool for making pretty plots and doing basic fitting
• Python - making use of matplotlib and polynomial fitting libraries
• R - powerhouse fitting program with tons of diagnostic plots

• Regression Analysis Tutorial and Examples
• Understanding Diagnostic Plots for Linear Regression Analysis