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Statistics LibreTexts

12.11: Statistical Literacy

Surgery for Weight Loss


Single Mean

Research on the effectiveness of surgery for weight loss reported here found that "The surgery was associated with significantly greater weight loss [than the control group who dieted] through 2 years (61.3 versus 11.2 pounds, P<0.001)."

What test could have been used and how would it have been computed?

What do you think?

For each subject a difference score between their initial weight and final weight could be computed. A t test of whether the mean difference score differs significantly from 0 could then be computed. The mean difference score will equal the difference between the mean weight losses of the two groups (61.3 - 11.2 = 50.1).