Statistical considerations for grants. Brian Healy. Comments from previous class. Change time of course Available on-line power calculators http://www.cs.uiowa.edu/~rlenth/Power/ Two-sided vs. one-sided Comparison of statistical packages. Review. Type I error Type II error
Statistical considerations for grants
Notice that the shaded area is still part of the null curve, but it is in the tail of the distribution
b=P(fail to reject the H0 | HA is true)
Power = P(reject Ho | HA is true) = 1 - b
Experimental question: What? How?
Sample selection: Who? How many?
Analysis: Is there an effect?
Conclusion: To whom?
Mean in treated young patients
Mean in treated old patients
Mean in untreated old patients
Mean in untreated young patients