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Statistics LibreTexts

12.11: Statistical Literacy

Skills to Develop

  • Effectiveness of Surgery for Weight Loss

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, \(P<0.001\))."

Example  \(\PageIndex{1}\): what do you think

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


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 (\(61.3 - 11.2 = 50.1\)).


  • Online Statistics Education: A Multimedia Course of Study ( Project Leader: David M. Lane, Rice University.