Description	a, b	Mode (a-1)/(a+b-2)	Percentiles
			2.5%	97.5%
(a) Perhaps most realistic	2, 50	2%	0.45%	10.45%
(b) Somewhat more   pessimistic	2, 20	5%	1.17%	23.82%
(c) Uniform, flat	1, 1	none	2.50%	97.50%
(d) Questionable choice	7, 5	60%	39.97%	88.19%