Concentrating on Whey: The Use of Statistics in Process Control
This interrupted case study follows the progress of Kenny, the head operator for a whey protein processing system, as he works with Cheryl, a quality management specialist, to implement control charts to monitor process variables. Students assume the role of Cheryl as she shows Kenny how to create a control chart, explains the different types of out-of-control behaviors seen in control charts, and demonstrates how to calculate process capability and capability index. Kenny uses this information to determine a probable cause of variation. Originally developed for a senior-level undergraduate statistical quality management course, this case study is also appropriate for courses focusing on quality management in industrial settings, as well as for a general undergraduate statistics course. Although familiarity with HACCP (Hazard Analysis Critical Control Points) principles is assumed, students are not expected to know about whey protein processing fundamentals.
- Differentiate between variables and attributes.
- Differentiate the appropriate uses for Xbar, R and s charts.
- Select the appropriate quality characteristic(s), rational subgroup, and sampling method for a given process.
- Construct and revise variable and attribute control charts.
- Evaluate control charts for out-of-control patterns.
- Explain why a given process is in control or out of control.
- Calculate process capability and process capability index and explain what the results mean in terms of process control.
- Calculate the quality rating of a product and explain what the results mean in terms of process contro.
KeywordsQuality management; quality rating; process control; process capability; capability index; control chart; variables and attributes; sampling method; food safety; food quality; whey
Educational LevelUndergraduate upper division, Graduate, Continuing education
Type / MethodsAnalysis (Issues), Discussion, Interrupted
Subject HeadingsFood Science / Technology | Statistics |