Simultaneous Comparisons of Multiple Treatments to Two (or More) Controls
STANFORD UNIV CA DEPT OF STATISTICS
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Dunnett 1955 developed a procedure comparing m treatments to one control with an exact overall type I error of alpha when all sampling distributions as normal. Sometimes it is desirable to compare m treatments to K or 2 controls. In particular, it is often desired to compare m treatments with two controls. For instance, several new treatments e.g., pain relievers could be compared to two standard treatments e.g., Aspirin and Tylenol. Alternatively, a standard treatment could be very expensive, difficult to apply andor have bad side effects, making it useful to compare each new treatment to both standard treatment and not treatment Placebo. Dunnetts method is expanded here to give comparisons of mean values for m treatments to mean values for K or 2 controls at an exact overall type I error of a alpha when all sampling distributions are normal. Tabled values needed to make exact simultaneous comparisons at alpha .05 are given for K2. An application is made to an illustrative example for the literature.
- Medicine and Medical Research
- Statistics and Probability