Fig 4. The association between soil-transmitted helminth infection or no deworming on tests of learning with exclusion of identified outlier investigations.
Diamond denotes the pooled standardized mean difference (SMD). Squares indicate the SMD in each study, with square sizes directly proportional to the weight contribution (%) of each study. Horizontal lines represent 95% confidence intervals (CI). The Z test for overall effect indicates non-significance given that P > 0.05. The chi-square test indicates that heterogeneity (P = 0.12, I2 = 33%) was reduced by outlier treatment. SD: standard deviation; CI: confidence interval; Std: standard; df: degree of freedom; I2: measure of variability expressed in %.