Help with an HP-67 Stat Pac I Program

[Namir]

I am looking at the Polynomial Approximation program in the HP-67 Stat Pac I (page 14-01 of the manual). The equations listed are a bit unclear to me. Can someone either provide me with an easier pseudo-code or better yet, a BASIC program? Or if some can point out a popular book or web site that offers a clear mathematical background

I have been curious about this program for years. I hope someone can help. Of course one can alway use polynomial regression, but my curiosity has me looking into how the program works.

Namir