# 12.11: Statistical Literacy

• • Contributed by David Lane
• Associate Professor (Psychology, Statistics, and Management) at Rice University

Learning Objectives

• 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?

Solution

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

## Contributor

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