Data were pooled across studies, and relative risks for categorical outcomes and weighted mean differences for continuous outcomes, weighted according to study sample size, were calculated.
将所有的研究的数据合成，对于分类变量效应指标为风险比，对于连续型变量效应指标为加权均数差，根据研究样本的大小来加权。
The calculation formulas of sample size based on the error limitation are given for estimation of population mean.
对于样本均值估计总体均值，给出了基于误差限制的样本容量的计算式。
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