Paint Tint Corporation

Late last month, Jim Runnels, a sales representative for the Paint Tint Corporation, was called to the
plant of Townhouse Paint Company, one of his largest accounts. The purchasing agent for Townhouse
Paint was complaining that the tubes of paint tint it had received over the last couple of weeks were not
within the specification range of 4.90 to 5.10 ounces.
The off-weighed tubes had not been detected by Townhouse's receiving clerks and had not been
weighed or otherwise checked by their quality control staff. The problem arose when Townhouse began to
use the tube of tinting agent and found that the paint colors were not matching the specifications. The
mixing charts used by the salespeople in Townhouse's retail stores were based on 5-ounce tubes of tinting
agent. Overfilled or underfilled tubes would result in improper paint mixes, and therefore in colors that did
not meet customer's expectations.
In consequence, Townhouse had to issue special instructions to its entire retail staff that would allow
them to compensate for the off-weight tubes. The Townhouse purchasing agent made it clear that a new
supplier would be sought if the problem recurred. Paint Tint's quality control department was immediately
summoned to assist in determining the cause to f the problem.
Paint Tint's quality manager, Ronald Wilson, decided to collect some data to analyze the problem. The
plant is a two shift operation and Wilson collected samples from each shift for 15 days. Samples always
consisted of 10 randomly selected tubes of paint tint . The data is provided in the spreadsheet named
PAINT DATA.XLS

1.

Analyze the data provided with respect to process control and process capability. Can
you identify any issues that may explain the weight problem?
To calculate σ, use the following approximation:
2.
How would you rate the ability of Paint Tint's production process to meet Townhouse
Paint's requirements? What are the implications of your evaluation?

3.

If Paint Tint ships 10,000 tubes of tint how many can Townhouse expect to be out of
specification (assuming nothing changes)?