Question

A behavioral psychologist wanted to know if making a public commitment to lose weight will make a difference in how much weight is actually lost. He obtained 14 volunteers who wanted to lose weight and randomly assigned them to one of two groups. The “commitment” group met together and each participant stood and announced an intent to lose weight and signed a pledge to adhere to the diet and exercise regimen. The “control” was placed on the same diet and exercise regimen, but did not stand to announce their intent to lose weight and did not sign a pledge to adhere to the regimen. The commitment group participants lost 13, 11, 13, 12, 10, 9,and 8 pounds; the control group participants lost 10, 6, 7, 5, 9, 6, and 8 pounds. Did making a commitment to adhere to the diet and exercise regimen make a significant difference in weight loss?

• What type of t test needs to be conducted?
• What is the calculated t statistic?
• Is this a one tail or 2 tail test?
• Are the findings significant at alpha .05? Explain what this means.

Answer 1