Biomedical subjects

D M Rom

Publications and source records attributed to D M Rom.

3 recordsLinked to original sources

PubMed1996

Testing for individual and population equivalence based on the proportion of similar responses.

This paper focuses on the classical problem of comparison of treatment effects. We show that we can base a simple and intuitive approach to comparison of two treatments on the proportion of similar responses. This approach is equivalent to the standard comparison of the treatment means in the normal case with equal known variances, but is quite different in other cases. Our approach applies under two different settings: testing a null hypothesis of no treatment difference against an alternative hypothesis of a difference, and testing the null hypothesis of at least a specific difference against an alternative hypothesis of equivalence. We develop our approach both for parallel groups (independent samples), and cross-over (paired samples) studies. The two situations give rise to the known concepts of population and individual equivalence. We present a graphical procedure to supplement the method.

Cross-Over Studies↗

PubMed1994

On closed test procedures for dose-response analysis.

This paper concerns the testing of a dose-response effect in medical studies. We consider two situations. The first is when the drug effect on a parameter of interest is likely to increase (or decrease) with increasing doses. We propose a procedure based on the closure principle of Peritz combined with an application of a closed testing procedure of Marcus et al. to a test proposed by Turkey et al. The second situation is the analysis of a drug effect where one might observe a reversal at higher doses. For this situation, we propose simultaneous examination of contrasts among the doses at each of several stages of the testing scheme. We calculate critical values for this procedure incorporating the correlation structure among the contrasts. Both procedures strongly control the family-wise error rate at the pre-determined alpha level. They also provide information about the shape of the dose response lacking in other commonly used procedures for testing against an ordered alternative hypothesis. We illustrate the procedures on two datasets.

Algorithms↗

PubMed1992

Strengthening some common multiple test procedures for discrete data.

This paper proposes modification of some commonly used multiple test procedures for testing problems that arise when the underlying distributions are discrete. These procedures have been shown as conservative because the exact nominal levels are unattainable. The amended procedures can achieve actual type I errors much closer to the nominal levels, thus giving rise to more powerful tests.

Animals↗