u Chart Formulas
QI Macros Can Calculate Them For You!
Draw a u Chart using QI Macros
- Select your data.
- Select u chart on QI Macros menu.
- QI Macros will do the math and draw the graph for you.
Go Deeper:
u Charts determine stability of "counted" data (e.g., errors per bill, dents in a car door, etc.) when there can be more than one defect per unit and the sample size varies.
Here is the formula used to calculate a u Chart.
cᵢ = number of nonconformities
nᵢ = sample size
Conforms with ANSI/ASQC B1, B2, B3 1996
NOTE: It is not possible to have negative limits on a u Chart. With that, any calculated value that is below 0 is automatically changed to 0.
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The u Chart is just one of the tools included in QI Macros SPC Software for Excel.
Why Choose QI Macros Over Other Control Chart Software?
Fast and Easy to Use
- Works right in Excel
- Create charts in seconds
- Easy to customize & share charts
- Free Training Anytime
Proven and Trusted
- More than 100,000 users
- In More than 80 countries
- Five Star CNET Rating - Virus free
Affordable
- Only $375 USD
Quantity Discounts Available - No annual subscription fees
- Free technical support
