Linear regression test of funnel plot asymmetry

Test result: t = -1.67, df = 10, p-value = 0.1250
Bias estimate: -1.3897 (SE = 0.8301)

Details:
- multiplicative residual heterogeneity variance (tau^2 = 0.8790)
- predictor: standard error
- weight:    inverse variance
- reference: Egger et al. (1997), BMJ