Control Chart for Variables by Guillermo Sanchez. August 1999, Email: guillerm@gugu.usal.es

This file has a package with online help about Control Chart for Variables in zip format.
To install: 
1 Extract the file with a zip utility (ex:winzip).  
2 Copy the folder QualityControl in the subdirectory of Mathematica: Addons\Applications
3 Open Mathematica and  in Help select: Rebuild Help Index. 
Then you find in addons help a new item : QualityControl where it is describe how work this package