Quality Control and Understanding Variation in Different Industries

Mica Thickness

Review the data from Ott on Mica Thickness measurements. The data shows samples of five from 40 batches of shipments.

Considering the funnel experiment literature and class experiment, Funnel data shows the results of such experiment. Discuss the four rules using XmR chart of each rule and related variation. It is helpful to produce the charts in sequence (side by side) to observe the impact of rules.

A classic paper by Mandel studied mail processing at the United States postal service (Mandel). The data represents pieces of mail processed (independent variable) and labor hours (dependent variable) required. Develop a regression control chart and discuss your findings. If a location uses 162 million pieces of mail, how would you explain labor hours to the management?

The table below shows the quarterly production for ten marketing staff at a company. At the end of each year the company first ranks the staff and based on the ranking awards cash bonuses.  Tap into understanding Variation (Wheeler, Tribus, etc.) to support your discussion. 

Develop a control chart of total production and discuss your findings.

How would you rank the staff and assign cash bonuses?

In a research study, workers suspected of having asthma are asked to record their lung function at work and away from work for a period of at least two weeks. The aim is to determine if the worker’s asthma is work – related. The lung function test used in this research is peak expiratory flow (PEF) which is expressed in milliliter per second (mL/s).  A worker who was suspected of having occupational asthma was asked to record his daily PEF four time daily (n) for a period of at least two weeks (14 days) while away from work (vacation). Here the sample size (n) is 4 and there are 14 subgroups. The data set is shown below.

Discuss the data arrangement, that is, group and subgroup, type of variation?

Considering our class discussion, review of Wheeler Chapter 3, Papers on understanding variation, develop a control chart and discuss your findings.

The worker returns to work and continues monitoring his lung function. The data set for the first 5 days after returning to work is shown below.

Plot the daily average and range for these five work days on away period control chart. Discuss your observations now. What is the state of the worker’s asthma at work?  

A food processing operation consists of mixing ingredients, forming and cooking. Figure below shows the cooking process where the formed material travels through a cooking oven on a conveyer belt. The raw material is subject to shrinkage due to the cooking process. The specification limits for shrinkage is between 5% and 9%. There are two machines operating two shifts daily.  A technician selects samples before and after cooking process and calculates percent shrinkage.  Table below shows the data set for several cooked samples taken from the upper and lower machines. The weight is in pounds.  Using quality control chart to evaluate data homogeneity, compare lower vs. upper machine. Is the supervisor’s claim that both machines are the same correct? Discuss. 

In a management meeting attended by senior managers of your company, you will hear from the CEO about flat sales in the last several months. That, unless the company reaches the target goal of $4 million sales in the next couple of months, the bonuses will be reduced, possibly reduce the sales budget and may even resort to sales force reduction. To support her decision, the CEO presents the sales data for the last several months as shown below.

Develop an XmR chart, educate the CEO on understanding variation/

How would you suggest to use the control chart for forecasting purpose?

What are your suggestions about the demand for $4M in sales? How can this be achieved?  Please be sure to have a substantive discussion.