APPLCATION PROBLEM

In the insulator case study of Section $4\mathrm{.}4,$ data were collected and charted on the number of machine blowups by cavity by day. The resulting control chart $($Figure $4\mathrm{.}14)$ showed a point above the upper control limit$.$ To determine differences between the cavities in the injection molding stage of the process, the team working on the process planned to construct two separate control charts for the data. Believing that the corner cavities $($cavities $1,4,5,$ and $8)$ were irvolved in a higher number of machine blowups, data were collected for an additional two weeks and subgrouped by cavity location $($i$.$e$.,$ by inside or comer cavity$).$ The resulting data are provided in Table $4\mathrm{.}9.$

TAble $4\mathrm{.}4$ Mackine Blorups by Day

$\backslash$table$[[$Day$,\backslash$table$[[$Number of$],[$Machine Blowups$]]],[1,24],[2,35],[3,26],[4,35],[5,27],[6,12],[7,23],[8,25],[9,16],[10,24],[11,24],[12,27],[13,17],[14,30],[15,22],[16,21],[17,27],[18,24],[19,30],[20,25],[$Total$,494]]$

$[$D$],$ Focus