Example of Capability Analysis

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Basic Analysis • Distributions • Additional Examples of the Distribution Platform • Example of Capability Analysis

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Example of Capability Analysis

Suppose you want to characterize the acidity of pickles. The lower and upper specification limits are 8 and 17, respectively.

1.

Select Help > Sample Data Library and open Quality Control/Pickles.jmp.

2.

Select Analyze > Distribution.

3.

Select Acid and click Y, Columns.

4.

5.

From the red triangle menu next to Acid, select Capability Analysis.

6.

Type 8 for the Lower Spec Limit.

7.

Type 17 for the Upper Spec Limit.

8.

Keep the rest of the default selections, and click OK.

9.

Click the Acid red triangle and deselect Histogram Options > Vertical.

Figure 3.21 Example of the Capability Analysis Report

The specification limits are added to the histogram so that the data can be visually compared to the limits. As you can see, some of the acidity levels are below the lower specification limit, and some are very close to the upper specification limit. The Capability Analysis results are added to the report. The CPK value is 0.510, indicating a process that is not capable, relative to the given specification limits.

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Help created on 3/19/2020