Notes on testing equality and interval estimation in Poisson frequency data under a three-treatment three-period crossover trial.
When the frequency of event occurrences follows a Poisson distribution, we develop procedures for testing equality of treatments and interval estimators for the ratio of mean frequencies between treatments under a three-treatment three-period crossover design. Using Monte Carlo simulations, we evaluate the performance of these test procedures and interval estimators in various situations. We note that all test procedures developed here can perform well with respect to Type I error even when the number of patients per group is moderate. We further note that the two weighted-least-squares (WLS) test procedures derived here are generally preferable to the other two commonly used test procedures in the contingency table analysis. We also demonstrate that both interval estimators based on the WLS method and interval estimators based on Mantel-Haenszel (MH) approach can perform well, and are essentially of equal precision with respect to the average length. We use a double-blind randomized three-treatment three-period crossover trial comparing salbutamol and salmeterol with a placebo with respect to the number of exacerbations of asthma to illustrate the use of these test procedures and estimators.
Department of Mathematics and Statistics, College of Sciences, San Diego State University, San Diego, CA, USA kjl@rohan.sdsu.edu.
Kung-Jong
KJ
Lui
Department of Statistics and Information Science, Fu-Jen Catholic University, New Taipei, Taiwan, ROC.
Kuang-Chao
KC
Chang
D000420:Albuterol / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D016018:Least-Squares Analysis; D008297:Male; D009010:Monte Carlo Method; D016012:Poisson Distribution; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D000068299:Salmeterol Xinafoate / Q000627:therapeutic use
D000068299:Salmeterol Xinafoate; D000420:Albuterol
Poisson distribution; count data; crossover design; equality; interval estimators; power; precision