Tables
Poisson Probabilities
r = 5 ~ 20

This table gives selected Poisson probabilities for values of r (conventionally called lambda, l) from 5 through 20. (5.0 is the highest value of r for which the chance of getting zero occurrences per unit of observation remains at all likely; p = 0.01; it is the upper limit of our normal Poisson Table). r = 10 is the point at which the Normal Distribution begins to be a good approximation for the Poisson Distribution. Probably for this reason, standard Poisson tables do not usually go higher than r = 20.

The likeliest number of occurrences (which is r, rounded down to the nearest whole number) is shown in bold. It is standard, for whole number r, that p(r) = p(r - 1).

Table for r = 5 ~ 20

 r = 5 r = 6 r = 7 r = 8 r = 9 r = 10 r = 15 r = 20 p(0) 0.0067 0.0025 0.0009 0.0003 0.0001 0.0000 0.0000 0.0000 p(1) 0.0337 0.0149 0.0064 0.0027 0.0011 0.0005 0.0000 0.0000 p(2) 0.0842 0.0446 0.0223 0.0107 0.0050 0.0023 0.0000 0.0000 p(3) 0.1404 0.0892 0.0521 0.0286 0.0150 0.0076 0.0002 0.0000 p(4) 0.1755 0.1339 0.0912 0.0573 0.0337 0.0189 0.0006 0.0000 p(5) 0.1755 0.1606 0.1277 0.0916 0.0607 0.0378 0.0019 0.0001 p(6) 0.1462 0.1606 0.1490 0.1221 0.0911 0.0631 0.0048 0.0002 p(7) 0.1044 0.1377 0.1490 0.1396 0.1171 0.0901 0.0104 0.0005 p(8) 0.0653 0.1033 0.1304 0.1396 0.1318 0.1126 0.0194 0.0013 p(9) 0.0363 0.0688 0.1014 0.1241 0.1318 0.1251 0.0324 0.0029 p(10) 0.0181 0.0413 0.0710 0.0993 0.1186 0.1251 0.0486 0.0058 p(11) 0.0082 0.0225 0.0452 0.0722 0.0970 0.1137 0.0663 0.0106 p(12) 0.0034 0.0113 0.0264 0.0481 0.0728 0.0948 0.0829 0.0176 p(13) 0.0013 0.0052 0.0142 0.0296 0.0504 0.0729 0.0956 0.0271 p(14) 0.0005 0.0022 0.0071 0.0169 0.0324 0.0521 0.1024 0.0387 p(15) 0.0002 0.0009 0.0033 0.0090 0.0194 0.0347 0.1024 0.0516 p(16) 0.0003 0.0014 0.0045 0.0109 0.0217 0.0960 0.0646 p(17) 0.0001 0.0006 0.0021 0.0058 0.0128 0.0847 0.0760 p(18) 0.0002 0.0009 0.0029 0.0071 0.0706 0.0844 p(19) 0.0001 0.0004 0.0014 0.0037 0.0557 0.0888 p(20) 0.0002 0.0006 0.0019 0.0418 0.0888 p(21) 0.0001 0.0003 0.0009 0.0299 0.0846 p(22) 0.0001 0.0004 0.0204 0.0769 p(23) 0.0002 0.0133 0.0669 p(24) 0.0001 0.0083 0.0557 p(25) 0.0050 0.0446 p(26) 0.0029 0.0343 p(27) 0.0016 0.0254 p(28) 0.0009 0.0181 p(29) 0.0004 0.0125 p(30) 0.0002 0.0083 p(31) 0.0001 0.0054 p(32) 0.0001 0.0034 p(33) 0.0020 p(34) 0.0012 p(35) 0.0007 p(36) 0.0004 p(37) 0.0002 p(38) 0.0001 p(39) 0.0001