Small size sampling?

Rakesh R. Pathak


Though small size samples can be planned and justified based on scarcity of time, money and manpower, there are situations making more accuracy a must and needing larger samples sizes. That’s why rare adverse drug reactions are identified only after a drug comes into the market and a large population is exposed to it. There are many more reasons for increasing the sample size and requirement of the study decides which criteria of accuracy should be tightened the most (e.g. avoiding type I error is more important or type II error).


Type I error, Type II error, Cohort, Statistical predictors

Full Text:



Pathak RR. Small size sampling. Int J Basic Clin Pharmacol 2012 Aug;1(1):43-4.

Oates JA. The science of drug therapy. In: Brunton LB, Lazo JS, Parker KL, editors. Goodman & Gilman's The Pharmacological Basis of Therapeutics. 11th ed. New York, NY: McGraw-Hill; 2005:135.

The Research Advisors. Sample Size Table. Available at Accessed 9 September 2012.

Explanations and Tables for

sample size for rare events. Available at Accessed 10 September 2012.

Raosoft. Sample size calculator. Available at Accessed 10 September 2012.

Bland M. An introduction to medical statistics, Third Edition. Oxford University Press, Great Britain, 2000.

Chow SC. Controversial Statistical Issues in Clinical Trials. Chapman and Hall/CRC Press, Taylor and Francis, New York; 2011:22.

Introduction to probability and statistics for computer engineers. Available at Accessed 9 September 2012.

Levine DM, Krehbiel TC, Berenson ML. (2010). Business Statistics: A First Course, 5th ed., Upper Saddle River, NJ: Prentice Hall; 2010: 295.

Type-1-error. Available at Accessed 5 September 2012.