Practical calculation of mean, pooled variance, variance, and standard deviation, in meta-analysis studies
Abstract
In order to perform the data analysis process, mean value and variance or standard deviation are required in a meta-analysis study for integrating data. However, sometimes reports published from studies only report Median, Range and Sample size. When no indication of the distribution of primary data (normal distribution or lack of normal distribution) is available, items such as mean and variance and standard deviation can be estimated based on simple formulas . The purpose of this article is merely to introduce proven formulas with applied examples.
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2. Borenstein M, Hedges LV, Higgins JP, Rothstein HR. Introduction to meta-analysis: John Wiley & Sons; 2011.
3. Borenstein M, Cooper H, Hedges L, Valentine J. Effect sizes for continuous data. The handbook of research synthesis and meta-analysis. 2009;2:221-35.
4. Carver RP. The case against statistical significance testing, revisited. The Journal of Experimental Education. 1993;61(4):287-92.
5. Kirk RE. Practical significance: A concept whose time has come. Educational and psychological measurement. 1996;56(5):746-59.
6. Thompson B. Significance, effect sizes, stepwise methods, and other issues: Strong arguments move the field. The Journal of Experimental Education. 2001;70(1):80-93.
7. Lipsey MW, Wilson DB. The efficacy of psychological, educational, and behavioral treatment: Confirmation from meta-analysis. American psychologist. 1993;48(12):1181.
8. Hozo SP, Djulbegovic B, Hozo I. Estimating the mean and variance from the median, range, and the size of a sample. BMC Medical Research Methodology. 2005;5(1):13.
9. Rudmin JW. Calculating the exact pooled variance. arXiv preprint arXiv:10071012. 2010.
10. La Nasa G, Caocci G, Efficace F, Dessi C, Vacca A, Piras E, et al. Long-term health-related quality of life evaluated more than 20 years after hematopoietic stem cell transplantation for thalassemia. Blood. 2013;122(13):2262-70.
11. Arian M, Mirmohammadkhani M, Ghorbani R, Soleimani M. Health-related quality of life (HRQoL) in beta-thalassemia major (β-TM) patients assessed by 36-item short form health survey (SF-36): a meta-analysis. Quality of Life Research. 2019;28(2):321-34.
12. Messina G, Colombo E, Cassinerio E, Ferri F, Curti R, Altamura C, et al. Psychosocial aspects and psychiatric disorders in young adult with thalassemia major. Internal and emergency medicine. 2008;3(4):339-43.
13. Amani F, Fathi A, Valizadeh M, Farzaneh E, Fattahzadeh-Ardalani G. Quality of life among Ardabil patients with beta-thalassemia major. International Journal of Research in Medical Sciences. 2015;3(11):3308-12.
14. Stensrud S, Roos EM, Risberg MA. A 12-week exercise therapy program in middle-aged patients with degenerative meniscus tears: a case series with 1-year follow-up. The Journal of orthopaedic and sports physical therapy. 2012;42(11):919-31.
| Files | ||
| Issue | Vol 7 No 1 (2020): Winter | |
| Section | Editorial(s) | |
| DOI | https://doi.org/10.18502/npt.v7i1.2294 | |
| Keywords | ||
| meta-analysis studies; practical calculation; mean; pooled variance; variance; standard deviation | ||
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How to Cite
1.
Arian M, Soleimani M. Practical calculation of mean, pooled variance, variance, and standard deviation, in meta-analysis studies. NPT. 2020;7(1):5-11.
