Fig. 4From: The effects of nutrients on stream invertebrates: a regional estimation by generalized propensity scoreComparison between the estimated effects of total nitrogen on invertebrate richness based on the generalized propensity score with/without the “outlier” stream site (the black point). The black solid line and the black dashed lines are the mean estimations and the corresponding 95% confidence boundaries including the outlier, respectively. The gray line is the mean estimation excluding the outlierBack to article page