u Chart Formulas

QI Macros Can Calculate Them For You!

Draw a u Chart using QI Macros

  1. Select your data.
  2. Select u chart on QI Macros menu.
  3. 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.

u chart formula

cᵢ = number of nonconformities
nᵢ = sample size

Conforms with ANSI/ASQC B1, B2, B3 1996

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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?

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