Mean and Mean difference are the two key statistical measures used in the statistical analysis. Both are essential for meta-analysis as well. Mean and Mean difference are used for the interpretation of a large set of values into a single number which explains the heterogeneity and variation among the individual values. However, one of a common challenge in meta-analysis is the unavailability of this data (mean and standard deviation).
Q & A Forum
Meta Analysis
Q: How can SD be estimated when only effect estimates with confidence intervals (CI) are available?
- The SE can be derived from the CI of the reported difference.
- If the statistical test is known, the appropriate conversion method should be used.
- If the test is not specified, sample size can guide formula selection:
- Sample size ≥ 60 → Use z-distribution (Formula 2).
- Sample size < 60 → Use t-distribution (Formula 4).
- Once SE is determined, within-group SD can be estimated using Formula 20.
