Statistical Literacy

Author(s)

David Lane

Surgery for Weight Loss

Prerequisites

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).

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