digraph G { N1 -> N4 N1 -> N6 N1 -> N8 N1 -> N10 N1 -> N12 N4 -> N5 N6 -> N7 N8 -> N9 N10 -> N11 N12 -> N13 N1 [ label="m", shape="parallelogram"] N5 [ label="a[,1]", shape="box"] N4 [ label="mean", shape="ellipse"] N7 [ label="a[,2]", shape="box"] N6 [ label="mean", shape="ellipse"] N9 [ label="a[,3]", shape="box"] N8 [ label="mean", shape="ellipse"] N11 [ label="a[,4]", shape="box"] N10 [ label="mean", shape="ellipse"] N13 [ label="a[,5]", shape="box"] N12 [ label="mean", shape="ellipse"] }