p chart and u Chart Formats
p chart and u chart control limit options available in the QI Macros
p charts and u charts can have upper control limits (UCL) and lower control limits (LCL) that vary with the sample size. The QI Macros provides users with options about how these control limits are displayed.
Flat or skyline limits without 1 and 2 sigma lines (default)
When you run a p chart or u chart in the QI Macros, the default format is "flat or skyline limits" that display the UCL, CL, LCL and your data.
How to Choose Between Flat (Skyline) and Wavy Limits
To change the QI Macros default from flat/skyline limits to wavy limits, click on Control Charts, then Control Chart Rules, then p/u UCL_LCL format.
A window will open showing the new format you are selecting. Click OK to change the format.
Now run the p chart or u chart again and the control limits will be wavy vs flat/skyline.
Here is a p chart with wavy control limits:
Flat Horizontal Lines When There is Little Variation in the Sample Size
p Chart UCL Limited to 100% Since it is a Fraction Defective Chart
Since the p chart is a fraction defective chart, the UCL is limited to 100% and the LCL is limited to 0%
Learn More...
- Option to Show or Hide Sigma Lines
- All Control Chart Menu Options
- p prime Control Chart Template
- u prime Control Chart Template
