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

tau^2 (estimated amount of total heterogeneity): 331.4395 (SE = 318.1791)
tau (square root of estimated tau^2 value):      18.2055
I^2 (total heterogeneity / total variability):   87.76%
H^2 (total variability / sampling variability):  8.17

Test for Heterogeneity: 
Q(df = 3) = 15.5098, p-val = 0.0014

Model Results:

estimate       se     zval     pval    ci.lb    ci.ub          
-29.9046   9.8706  -3.0297   0.0024 -49.2506 -10.5586       ** 

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