The Washers.jmp sample data contains defect data for two different lot sizes from the ASTM Manual on Presentation of Data and Control Chart Analysis, American Society for Testing and Materials (1976). To view the differences between constant and variable sample sizes, you can compare charts for Lot Size and Lot Size 2.
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Select Analyze > Quality and Process > Control Chart Builder.
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Select Shewhart Attribute from the drop down to change the chart to an attribute chart.
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Figure 3.16 p-chart of # defective
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Figure 3.17 p-chart of # defective with sample size
To view the differences between constant and variable sample sizes, you can compare charts for Lot Size and Lot Size 2 by simply dragging the variables to the nTrials zone.