There is an ATS developed program called **pprob** that will generate a table of poisson probabilities. You can install
**pprob** over the internet by typing **search nbvargr** (see
How can I use the search command to search for programs and get additional help? for more information about using
**search**).
Note: **pprob** is a program called by **nbvargr**.

Now, let’s try the program. First, let’s generate a table with a lambda (the mean of a poisson distribution) of 2 and then a table with a lambda of 2.7. In both examples the number of categories will run from 0 to 10.

pprob, mean(2) n(10)Poisson Probabilities for lambda = 2 k prob cumprob invcum 1. 0 .1353353 .1353353 .8646647 2. 1 .2706706 .4060059 .5939941 3. 2 .2706706 .6766764 .3233236 4. 3 .180447 .8571234 .1428766 5. 4 .0902235 .947347 .052653 6. 5 .0360894 .9834364 .0165636 7. 6 .0120298 .9954662 .0045338 8. 7 .0034371 .9989033 .0010967 9. 8 .0008593 .9997625 .0002375 10. 9 .0001909 .9999535 .0000465 11. 10 .0000382 .9999917 8.34e-06pprob, mean(2.7) n(10)Poisson Probabilities for lambda = 2.7 k prob cumprob invcum 1. 0 .0672055 .0672055 .9327945 2. 1 .1814549 .2486604 .7513396 3. 2 .2449641 .4936245 .5063756 4. 3 .2204677 .7140922 .2859078 5. 4 .1488157 .8629079 .1370921 6. 5 .0803605 .9432684 .0567316 7. 6 .0361622 .9794306 .0205694 8. 7 .0139483 .9933788 .0066212 9. 8 .0047075 .9980864 .0019136 10. 9 .0014123 .9994987 .0005013 11. 10 .0003813 .99988 .00012