U-Charts
- Open Attribute Data U Chart Defects.xlsx. U Charts (for Defects) can have fixed or varying subgroup sizes.
- Select SigmaXL > Control Charts > Attribute Charts> U. Ensure that the entire data table is selected. If not, check Use Entire Data Table. Click Next.
- Select Defects, click Numeric Data Variable (Y) >>. Select N, click Subgroup Column or Size >>. Check Tests for Special Causes.
- Click OK. The resulting U-Chart is shown:
This is a stable process, with no tests for special causes flagged.