Individual Measurement and Moving Range Charts Example

The Pickles.jmp data in the Quality Control sample data folder contains the acid content for vats of pickles. Because the pickles are sensitive to acidity and produced in large vats, high acidity ruins an entire pickle vat. The acidity in four vats is measured each day at 1, 2, and 3 PM. The data table records day, time, and acidity measurements. You can create Individual Measurement and Moving Range charts with date labels on the horizontal axis.

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

Select Analyze > Quality and Process > Control Chart > IR.

Select both Individual Measurement and Moving Range chart types.

Select Acid and click Process.

Select Date and click Sample Label.

Click OK.

The individual measurement and moving range charts shown in Figure 4.20 monitor the acidity in each vat produced.

Note: A Median Moving Range chart can also be evaluated. If you choose a Median Moving Range chart and an Individual Measurement chart, the limits on the Individual Measurement chart use the Median Moving Range as the sigma, rather than the Average Moving Range.

Figure 4.20 Individual Measurement and Moving Range Charts for Pickles Data