95% Confidence Interval for a Poisson Variable (Xt)

Cases	Lower	Upper
0	0	3.69
1	.025	5.57
2	.242	7.22
3	.619	8.77
4	1.09	10.24
5	1.62	11.67
6	2.2	13.06
8	3.45	15.76
10	4.8	18.39
15	8.4	24.74
20	12.22	30.89
25	16.18	36.9
30	20.24	42.83
35	24.38	48.68
40	25.58	54.47
45	32.82	60.21
50	37.11	65.92

* adapted from Perason and Hartley, 1966

If cases are in between the numbers listed, a linear interpolation can estimate the value. This table is for demonstration purposes only, and the analyst is encouraged to used more accurate tables available on varius computer programs.