February, 2003
© 2000, 2001, 2003 Scott S. Emerson, M.D., Ph.D.
Session 1- Fixed Sample Design: 110
Case Study: Statistical Design Issues
Defining the criteria for statistical evidence
Frequentist criteria
·Type I error: Probability of falsely rejecting the null hypothesis
-Two-sided hypothesis tests:      0.05
-One-sided hypothesis tests:      0.025
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·Power: Probability of correctly rejecting the null hypothesis (1 - type II error)
-Popular choice: 80%