Proportion Defective Chart to monitor ARSAN Sachet Water Production Process

Abstract

This study applies the proportion defective control chart (p-chart) to monitor the fraction of non-conforming or defective bags of sachet water produced by ARSAN Water Company in Ikot Ekpene.  The aim is to inform the ARSAN water company on how to detect defective bags in the production process. The variation in the production was examined for seventy-six (76) days within the peak period of sales (from February to April, 2024).  A sample of 100 bags of sachet water was taken each day for the 76 days, and the number of leaked (defective) bags of water was ascertained in each sample from the production department. The p-chart, Upper Control Limit (UCL), and the Lower Control Limit (LCL) for the proportion of defective bags in the 76 days sample of 100 in each case were constructed.  The sample proportion defective remained within the upper and the lower control limits of the p-chart, except for the two sample proportion defectives submitted for days 32 and 76, which were out of control. This indicates that the production process is somewhat out of control. However, on average, there were about 5.7% defective bags of sachet water every day, indicating a high proportion of defectives.  The ARSAN Water Company's process with the defective bags is not acceptable.  Hence, the production unit should employ other quality inspection and assurance procedures to minimize the number of defective bags in the production process.