Worksheet 23: The Potential Outcomes Model

Worksheet 23: The Potential Outcomes Model#

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Antonioli and Reveley (2005) investigated whether swimming with dolphins could be therapeutic for patients suffering from clinical depression.

  • Recruited 30 subjects with a clinical diagnosis of mild to moderate depression.

  • Randomly assigned subjects to one of two treatment groups of 15 subjects each. Both groups engaged in one hour of swimming and snorkeling each day, but

    • Dolphin Therapy group did so in the presence of bottlenose dolphins

    • Control group did not.

  • At the end of two weeks, each subject’s level of depression was evaluated.

    • 10 subjects in the Dolphin Therapy group showed improvement

    • 3 subjects in the Control group showed improvement

  1. What is the null hypothesis for this experiment?

  2. When you used the potential outcomes applet, what was your \(p\)-value for the difference in means between the treatment and control group? Should you reject the null hypothesis at level \(\alpha = 0.05\)?