Vol. 8, No. 3

March 2006

PQ Systems

Right First Time DVD

Quality Quiz: With a video!

Six Sigma

Data in everyday life

Bytes and pieces

FYI: Current releases


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Quality Quiz:

Click here for Quality Quiz Video Explanation

Allie Katt, recently appointed as a quality technician at Natural Dairy Company, has been charged with creating a control chart for the cottage cheese production line. Each day, the plant produces the number of containers that has been ordered the day before. These orders range from 400 to 2,300 per day.

The final setp on the prodution line is a check for Ph values by an inspector, who removes cartons that fail his test. Allie has just learned charting techniques, and determines--based on what she remembers about control charts--that this process demands the use of a p-chart, a chart that measures the percentage of rejects or defects. Fortunately, she has a copy of SQCpack to create the following chart:

"Aha!" she exclaims when she inspects the chart. Spotting a point outside the upper control limits, she notes, "Out of control on February 2 (sample 10) and February 17 (sample 21)," and shuts the line down to address the offending process. Smug in the demonstration of her ability to read the chart, she forms a team to disassemble the fill machine to identify the problem.

A visiting consultant, Awana Gohome, happens to be in the plant that day, and stops to examine the chart that Allie has been studying. Noting that the number of cartons inspected in each sample varies by a large margin, Awana states in her firm consultant voice that the chart is invalid.

Is Awana right?

a) Yes. The process cannot be assessed accurately under these circumstances.

b) No. Awana Gohome is just a nitpicking consultant. She should go gome.

Copyright 2006 PQ Systems.
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