Clinical Trials

Clinical Trials: A Practical Guide ■❚❙❘When assessing the treatment effect in a two-arm parallel design using t-test, theassumptions of approximate normality of distribution, approximate equality ofvariance, independence of observations, and comparability of two treatmentgroups at baseline should be borne in mind. When such assumptions are notreasonable, alternative methods such as a nonparametric approach or regressionmodeling should be considered.References1. Pocock SJ. Clinical Trials: A Practical Approach. Chichester: John Wiley & Sons, 1983.2. Hoel PG. Introduction to Mathematical Statistics, 2nd edition. New York: John Wiley & Sons, 1954.3. Altman DG. Practical Statistics for Medical Research. London: Chapman & Hall, 1999.4. Kirkwood B, Sterne J. Essential Medical Statistics, 2nd edition. Oxford: Blackwell Publishing, 2003.5. Lee AFS. Student’s t distribution and student’s t statistics. In: Encyclopedia of Biostatistics.Armitage P, Colton T, editors. New York: John Wiley & Sons, 1998:4396–7.6. Tong YL. Normal distribution. In: Encyclopedia of Biostatistics. Armitage P, Colton T, editors.New York: John Wiley & Sons, 1998:3064–7.7. Wilcoxon, F. Individual comparisons by ranking methods. Biometrics 1945:1:80–3.8. Mann H, Whitney D. On a test of whether one of two random variables is stochastically largerthan the other. Ann Math Stat 1947;18:50–60.9. Conover, WJ. Practical Nonparametric Statistics, 3rd edition. New York: John Wiley & Sons, 1999.215