February, 2003
© 2000, 2001, 2003 Scott S. Emerson, M.D., Ph.D.
Session 1- Overview: 60
Statistical Issues
Because the estimate of the treatment effect is no longer normally distributed in the presence of a stopping rule, the frequentist inference typically reported by statistical software is no longer valid
The standardization to a Z statistic does not produce a standard normal
·The number 1.96 is now irrelevant
·
Converting that Z statistic to a fixed sample P value does not produce a uniform random variable  under the null
·We cannot compare that fixed sample P value to 0.025