Quality Quiz:

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Last month, we saw Kohl Minor, assistant quality manager at the Blackern Dirt Coal Mine, using sophisticated linear regression formulas-or at least, stumbling into regression accidentally after his Harley-loving boss, Hal Zangels, ridiculed his use of the wrong statistical tool to pursue his analysis.

Kohl's CHARTrunner scatter diagram finally demonstrated the relationship between output and cost.

Emboldened by his foray into regression analysis, Kohl decides to prepare a PowerPoint presentation for the new plant manager, Ray O. Sonshine. When he shows his CHARTrunner chart to Hal Zangels, though, Hal asks about his calculation of the t statistic. "What in the devil does 't-statistic=5.08' mean?" he bellows.

"Well," Kohl responds slowly. "The 't' refers to the time that the analysis took place. It was done at 5:08 a.m., after the second shift," he explains. "We'll need to generate a chart for the other shifts as well."

Apparently that response satisfied Hal Zangels. Is Ray O Sonshine likely to see this explanation as accurate?

a) Not if he's ever looked at a scatter diagram before.

b) Yes, he will correctly support Kohl's suggestion about timing the next analysis to reflect other shifts.

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