Attributes Control Charts of Three Paint Companies
Keywords:
Statistical Quality Control, Chance Variation, Assignable Variation, Product ControlAbstract
This study investigated three attribute control charts of three paint companies. The Paint Companies were De Express Integrated Services Limited, Portland Paints & Products Limited and Marshal Paint and Chemical Industries Limited. The three paint companies’ monthly paint production (gallons) and monthly number of defects per gallon from March 2022 to March 2023. Three attribute charts were considered: the P Chart, NP chart, and U Chart. The paired t-test statistic was used to test for a significant difference between monthly production and the monthly number of paint defects by the companies. The results are as follows: -The three Paint Companies’ total Paint Production (in gal.) distribution seems the same (or similar), and it also showed that the joint variability of two paint companies is constant (i.e. De Express Integrated Services Ltd and Marshal Paint and Chemical Industries Limited). In conclusion. The U chart gave a similar result to the P chart, while the NP Chart contradicted it (i.e. showing no paint sample is out of control).
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