Certified Production & Operations Manager (POM) Practice Exam

Which control chart combination should be used when weighing jars of pickles to ensure they meet the ideal weight of 11 oz?

1. c-chart only

2. x-bar chart and R-chart

3. p-chart and c-chart

4. individual chart and moving range chart

The correct answer is: x-bar chart and R-chart

The use of an x-bar chart and an R-chart is appropriate for monitoring the weight of jars of pickles to ensure they meet the ideal weight specification of 11 oz due to the nature of the data involved. When weighing jars, you are dealing with continuous data – specifically, the weight of each jar. The x-bar chart is designed to monitor the mean of a process when samples of items are taken over time. It provides insight into how the average weight of the jars varies, which is crucial when trying to maintain target specifications. The R-chart is used in conjunction with the x-bar chart to monitor the variability within the samples. In this context, it helps to assess the consistency of the jar weights over time. By tracking both the mean and range of the samples, you can identify if any changes in the process might lead to deviations from the desired weight of 11 oz. In contrast, other options do not suit the continuous nature of the product being evaluated. A c-chart is used for monitoring count data, such as the number of defects, rather than continuous measurements like weight. The p-chart is used for attributes data, which involve pass/fail or yes/no decisions. An individual chart and moving range chart are useful for cases where