Principles of sample size calculation
In most areas in life, it is difficult to work with populations and hence researchers work with samples. The calculation of the sample size needed depends on the data type and distribution. Elements include consideration of the alpha error, beta error, clinically meaningful difference, and the varia...
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| Format: | Article |
| Language: | English |
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Wolters Kluwer Medknow Publications
2010-01-01
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| Series: | Indian Journal of Ophthalmology |
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| Online Access: | http://www.ijo.in/article.asp?issn=0301-4738;year=2010;volume=58;issue=6;spage=517;epage=518;aulast=Gogtay |
| Summary: | In most areas in life, it is difficult to work with populations and hence researchers work with samples. The calculation of the sample size needed depends on the data type and distribution. Elements include consideration of the alpha error, beta error, clinically meaningful difference, and the variability or standard deviation. The final number arrived at should be increased to include a safety margin and the dropout rate. Over and above this, sample size calculations must take into account all available data, funding, support facilities, and ethics of subjecting patients to research. |
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| ISSN: | 0301-4738 1998-3689 |