Certified Production & Operations Manager (POM) Practice Exam

Which type of control chart should be used to measure the number of defects after a hotel room cleaning?

1. p-chart

2. c-chart

3. x-bar chart

4. R-chart

The correct answer is: c-chart

The use of a c-chart is appropriate for measuring the number of defects in a fixed sample size, such as the number of defects found after cleaning hotel rooms. A c-chart is specifically designed for count data where the focus is on the number of occurrences of defects within a specific area of opportunity. In this case, each hotel room provides a 'unit' where defects can be counted, making the c-chart an effective tool for monitoring the performance of the cleaning process over time. In contrast, a p-chart is used to measure the proportion of defective items in a sample and is more suitable when you are dealing with a varying sample size. The x-bar chart and R-chart are utilized for continuous data and variations among samples, focusing on averages and range measurements, which are not applicable for counting discrete defects in the context of hotel room cleaning. Thus, the c-chart is the best choice given the scenario's specifics.