Vol. 7, No. 05
After three or four strikes, Marty Graw is out—at least with respect to Natural Butter Company. (Marty Graw gave his boss, Jack D. Ripper, capability results on a process that he was trying to improve, showing a Cpk of .78. Soon after that, he was gone.)
He has been replaced, not by one, but by two quality managers: Marsha Mallow and Maura Thesame, who will share the responsibilities that have done Marty in. The two quickly become known as the Dynamic Duo, since they work so closely together and often finish each other’s sentences. “Hey, let’s do a PowerPoint presentation…” Marsha says, “….showing all the data sets that we have,” Maura adds. “This will be a chance to demonstrate how much data we deal with,” Marsha points out, “and will educate the managers,” Maura says.
The first slide that the two prepare is a histogram reflecting package weight data.
Jack D. Ripper, their boss, asks the Duo about the shape of the distribution. “It’s not a perfectly normal distribution,” says Marsha, “…but it’s close enough,” Maura adds.
Jack presses his point: “Well, then, what about the Chi-squared value?” All eyes go to the chart, which indicates a Chi-squared value of 7.43. “What does this show about the package weight process?”
Marsha jumps in with an authoritative response: “Chi-squared values of 7.43 are great!” she says, “…the higher the Chi-squared, the better,” Maura adds.
Does their response reflect their superior understanding of chi-square?
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