Control Chart Suggestion
Control Chart Description
The np control chart are used to monitor the number of nonconforming units in samples of inspected units. A nonconforming unit is a product which fails to meet at least one specified requirement. There is a difference between a defect and defective, as there is between a nonconformity and nonconforming unit. The np-chart control chart is used with discrete/attribute defective data when the sample size is greater than 50. The sample size must be constant; this control chart is only valid if data is collected in same-size subgroups.
Control Chart Formulae
Control Chart Example
- Proportions Control Charts
- Case Study: Using np Charts To Address On-Time Medication Delivery
- Steps in Constructing an np-Chart
- Additional Control Chart Links
Wheeler, D.J., & Chambers, D.S. (1992). Understanding Statistical Process Control. Knoxville, TN: SPC Press.