Volume: 6 Issue: 1
Year: 2018, Page: 3-8,
Introduction: After confirmation of any line and area of Research work, the Basic Question starts with Collection of Sample size determination, but before that in a health science research "why statistical methods are so important?" Simple answer is that, statistical methods are used throughout a study that includes planning, designing, collecting data, analyzing and drawing meaningful interpretation and report the findings. Hence, it is important that a researcher knows the concepts of at least basic statistical methods used at various stages of a research study. This helps the researcher in the conduct of an appropriately well-designed study leading to valid and reliable results that can be generalized to the population. A well-designed study possesses fewer biases, which intern gives precise, valid and reliable results. There are many statistical methods and tests that are used at various stages of a research. In this communication, we discuss the overall importance of statistical considerations in medical research with the main emphasis on estimating minimum sample size for different study objectives.
Keywords: Biostatistics, Medical Research, Confidence Interval, Probability, Sample size.
1. Daniel WW. Biostatistics: A Foundation for Analysis in Health Sciences. 7 th ed. Singapore, Asia: John Wiley and Sons Pte. Ltd.; 2004
2. Bland M. An Introduction to Medical Statistics. 2 nd ed. England: Oxford University Press; 1995.
3. Applegate KE, Crewson PE. Statistical literacy. Radiology 2004;230:613-4.
4. Larson MG. Descriptive statistics and graphical displays. Circulation 2006;114:76-81.
5. McCluskey A, Lalkhen GA. Statistics III: Probability and statistical tests. Contin Educ Anaest Crit Care Pain 2007;7:167-70.
6. Montori VM, Kleinbart J, Newman TB, Keitz S, Wyer PC, Moyer V, et al. Tips for learners of evidence-based medicine: 2. Measures of precision (confidence intervals). CMAJ 2004;171:611-5.
7. Curran-Everett D. Explorations in statistics: Confidence intervals. Adv Physiol Educ 2009;33:87-90.
8. du Prel JB, Hommel G, Röhrig B, Blettner M. Confidence interval or P-value?: Part 4 of a series on evaluation of scientific publications. Dtsch Arztebl Int 2009;106:335-9.
9. Gardner MJ, Altman DG. Confidence intervals rather than P-values: Estimation rather than hypothesis testing. Br Med J (Clin Res Ed) 1986;292:746-50.
10. Poole C. Low P-values or narrow confidence intervals: Which are more durable? Epidemiology 2001;12:291-4.
11. Rigby AS. Getting past the statistical referee: Moving away from P-values and towards interval estimation. Health Educ Res 1999;14:713-5.
12. Potter RH. Significance level and confidence interval. J Dent Res 1994;73:494-6.
13. Evans SJ, Mills P, Dawson J. The end of the P value? Br Heart J 1988;60:177-80.
14. Attia A. Why should researchers report the confidence interval in modern research? Middle East Fertil Soc J 2005;10:78-81.
15. Chow CS, Wang H, Shao J. Sample Size Calculation in Clinical Research. USA: Chapman and Hall/CRC Press; 2003.
16. Wittes J. Sample size calculations for randomized controlled trials. Epidemiol Rev 2002;24:39-53.
17. Endacott R, Botti M. Clinical research 3: Sample selection. Accid Emerg Nurs 2007;15:234-8.
18. Neely JG, Karni RJ, Engel SH, Fraley PL, Nussenbaum B, Paniello RC. Practical guides to understanding sample size and minimal clinically important difference (MCID). Otolaryngol Head Neck Surg 2007;136:14-8.
19. Devane D, Begley CM, Clarke M. How many do I need? Basic principles of sample size estimation. J Adv Nurs 2004;47:297-302.
20. Columb OM, Stevens A. Power analysis and sample size calculations. Curr Anaesth Crit Care 2008;19:12-4.
21. Brasher PM, Brant RF. Sample size calculations in randomized trials: Common pitfalls. Can J Anaesth 2007;54:103-6.
22. Schulz KF, Grimes DA. Sample size calculations in randomised trials: Mandatory and mystical. Lancet 2005;365:1348-53.
23. Jones SR, Carley S, Harrison M. An introduction to power and sample size estimation. Emerg Med J 2003;20:453-8.
24. Donner A. Approaches to sample size estimation in the design of clinical trials - A review. Stat Med 1984;3:199- 214.
25. Lwanga KS, Lemeshow S. Sample Size Determination in Health Studies: A Practical Manual. Geneva: WHO; 1992.
26. Campbell MJ, Julious SA, Altman DG. Estimating sample sizes for binary, ordered categorical, and continuous outcomes in two group comparisons. BMJ 1995;311:1145- 8.
27. Parker AR, Bermman GN. Sample size: More than calculations. Am Stat 2003;57:166-70.
28. Lenth VR. Some practical guidelines for effective sample size determination. Am Stat 2001;55:187-93.
29. Eng J. Sample size estimation: How many individuals should be studied? Radiology 2003;227:309-13.
30. Florey CD. Sample size for beginners. BMJ 1993;306:1181- 4.
31. Woodward M. Sample size, power and minimum detectable relative risk in medical studies. J R Stat Soc Series DStat1992;41:185-96.
32. Bacchetti P, Wolf LE, Segal MR, McCulloch CE. Ethics and sample size. Am J Epidemiol 2005;161:105-10.
Agnihotram G. Standard statistical methods and calculation of sample size in Medical education research.Perspectives in Medical Research 2018;6(1):3-8.