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. 2021 Aug 31;13(9):3054. doi: 10.3390/nu13093054

Table 1.

Formulae used for data extraction for continuous outcomes.

Name Formulae
Formula for combining groups—mean Mean = N1M1 + N2M2/N1 + N2
Formula for combining groups—SD SD = square root [(N1 − 1)SD12 + (N2 − 1)SD22 + (N1N2/N1 + N2) × (M12 + M22 − 2M1M2)]/
(N1 + N2 − 1)
Formula for imputing
correlation coefficient		 Corr = (SDE2 + SDC2 − SDdiff2)/(2 × SDE × SDC)

N—sample size, M—mean, SDE—standard deviation of experimental intervention, SDC—standard deviation of control intervention, SDdiff—difference between experimental and control interventions’ SD.