Why are there 2 different versions of the course?

There are 2 different versions of each course depending on which textbook edition you are using. The current required textbook is:

"The Six Sigma Handbook, Third Edition" by Thomas Pyzdek and Paul Keller (Publisher McGraw-Hill; 3rd edition (October 12, 2009))

Book Details:
ISBN-10: 0071623388
ISBN-13: 978-0071623384
Format: Hardcover, 560 pages
Pub. Date: October 12, 2009
Publisher: McGraw-Hill Professional
Edition Number: 3

However, students using the now discontinued textbook:

The Six Sigma Handbook: The Complete Guide for Green Belts, Black Belts, and Managers at All Levels, Revised and Expanded Edition by Thomas Pyzdek (Publisher: McGraw-Hill; 2nd revised edition (March 20, 2003))

Product Details:
ISBN: 0071410155
Format: Hardcover, 848pp
Pub. Date: March 2003
Publisher: McGraw-Hill Companies, The
Edition Description: Revised and Expanded Edition
Edition Number: 2

Can access a compatible version of the program by clicking on the "2nd edition access" link.