A quality engineer assesses whether the process used to manufacture light bulbs is in control. The engineer tests 500 light bulbs each hour for three 8-hour shifts and records the number of bulbs that did not light (defectives).
Because the data are counts of defectives, you can use this data to demonstrate NP Chart.
|Subgroup ID||The subgroup identification number|
|Defectives||The number of light bulbs that did not light in the subgroup|