C Chart Example
C charts monitor the number of nonconformities in an entire subgroup, made up of one or more units.
Note: When you generate a C chart and select Capability, JMP launches the Poisson Fit in Distribution and gives a Poisson-specific capability analysis.
In this example, a clothing manufacturer ships shirts in boxes of ten. Prior to shipment, each shirt is inspected for flaws. Because the manufacturer is interested in the average number of flaws per shirt, the number of flaws found in each box is divided by ten and then recorded.
1. Select Help > Sample Data Library and open Quality Control/Shirts.jmp.
2. Select Analyze > Quality and Process > Legacy Control Charts > C.
3. Select # Defects and click Process.
4. Select Box and click Sample Label.
5. Select Box Size and click Sample Size.
6. Click OK.
Figure 12.24 C ChartÂ
