A wheel‐bearing manufacturer owns two plants, both in Illinois.

She wishes to see if money for health costs can be reduced if a wellness program is instituted. One plant (E) is selected for a yearlong experimental program that includes health screening and individually tailored fitness activities. The second plant (C) is the nonequivalent control group. Absence‐due‐to‐sickness rates, operationally defined as the number of sick days per year per 100 employees, are measured at the beginning and the end of the experimental year. What follows are four sets of results. Construct a graph for each and decide which (if any) provide evidence of program effectiveness. For those outcomes not supporting the program’s effectiveness, provide an alternative explanation for the experimental group’s apparent improvement.

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Outcome 1 E: C: Outcome 2 E: C: pretest = 125 pretest = 125 Outcome 4 E: C: pretest = 125 pretest = 100 Outcome 3 E: pretest = 125 C: pretest 130 = pretest = 125 pretest 110 = posttest = 100 posttest = 125 posttest = 100 posttest 100 = posttest = 100 posttest = 105 posttest = 100 posttest = 110