Tools
Concepts
Interpretation & Calculations
Histograms, Process Capability
Applications
Key Success Factors for the Implementation of SPC
How to Study Process Capability
SPC to Improve Quality, Reduce Cost
Use Of SPC To Detect Process Manipulation
U Chart Calculations
Plotted statistic for the U Attribute Control Chart
The average count of occurrences per unit of a criteria of interest in sample of items
where nj is the sample size (number of units) of group j.
Center Line
where nj is the sample size (number of units) of group j, and m is the number of groups included in the analysis.
UCL , LCL (Upper and Lower Control Limit)
where nj is the sample size (number of units) of group j and u-bar is the Average percent.
The U chart control limits vary for each sample based on its sample size, but are easily calculated using our SPC software.
See also:
When to Use an Attribute U Chart/a>
Interpreting an Attribute U Chart
Learn more about the SPC principles and tools for process improvement in Statistical Process Control Demystified (2011, McGraw-Hill) by Paul Keller, in his online SPC Concepts short course (only $39), or his online SPC certification course ($350) or online Green Belt certification course ($499).
