Is the SPC rules interpretation different in 11.0?
The default settings for the rule violations in 11.0 are based on the Nelson Rules. The interpretation of the rule violations has changed slightly. For example, the default in 10.x for the Trend rule was 6 of 6 which required 7 points and 6 transitions in the same direction. After further investigation, 11.0 was changed to be consistent with industry standard interpretations of the Nelson Rules. In version 11.0, 6 of 6 means 6 points in the data set with 5 transitions in the same direction. You can change this setting by changing the configuration of the individual rule in the display. Changing the setting for the Trend rule to 7 of 7 will make the rule violations the same in both versions. For further explanation, see http://www.qualityamerica.com/knowledgecente/articles/CQEIVH3e.html. In Figure IV.27, Test #3 that shows 6 points and the 6th point is the alarm, not the 6th transition point (meaning the 7th point in the subset). For more information on SPC rules, refer to the Statistic
