Random-Effects Model (k = 4; tau^2 estimator: REML)

tau^2 (estimated amount of total heterogeneity): 0 (SE = 51.7477)
tau (square root of estimated tau^2 value):      0
I^2 (total heterogeneity / total variability):   0.00%
H^2 (total variability / sampling variability):  1.00

Test for Heterogeneity: 
Q(df = 3) = 0.5962, p-val = 0.8973

Model Results:

estimate       se     zval     pval    ci.lb    ci.ub          
-19.4683   3.9835  -4.8873   <.0001 -27.2758 -11.6608      *** 

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Signif. codes:  0 *** 0.001 ** 0.01 * 0.05 . 0.1   1