plot diagnostics line unclear if mean leverage

hey!

just a quick question: is the line in the plotDiagnositcs plot in the middle the mean average (coefficients/ number of observations) or 2*(coefficients/number of observations)? Thanks!:)

http://www.mathworks.de/de/help/stats/nonlinear-regression-1.html#btb51xu-4

fyi: Leverage is a measure of the effect of a particular observation on the regression predictions due to the position of that observation in the space of the inputs. In general, the farther a point is from the center of the input space, the more leverage it has. Because the sum of the leverage values is p, an observation i can be considered as an outlier if its leverage substantially exceeds the mean leverage value, p/n, for example, a value larger than 2*p/n.