.l("config.kg")
grid([0 10 1];[0 1 0.1])

:"Plot chi-square PDF with nu=3 and fill area"
:"starting at 0.9'th quantile; then re-draw"
:"the grid and mark the border of the area"
:"with a vertical line"
plot(x2.pdf(3;))
area(b::x2.qf(3;0.9);10;0)
grid([0 10 1];[0 1 0.1])
vline(b)
draw()