Standardized DNOM Charts

Section 5 Short Run SPC

Lesson S05-02

Text: Section 5 pages 4 – 12

Duration: 18 minutes

Handling Standard Deviation Differences

As discussed above, when the part types do not have similar standard deviations, the DNOM method and charts are invalid. To account for differences in variation between the part types, a Standardized DNOM (to monitor location) and Standardized S chart (to monitor variation) may be created.

Next, we briefly illustrate a procedure to test for statistical differences in variation among groups. The technical details are left for a course in hypothesis testing.

Standardized DNOM Chart Data

Standardized DNOM Chart Setup

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About Steven Wachs

Steven Wachs has 25 years of wide-ranging industry experience in both technical and management positions. Steve has worked as a statistician at Ford Motor Company where he has extensive experience in the development of statistical models, reliability analysis, designed experimentation, and statistical process control.