I have some data that includes the output of a Poisson Log Link model, that aims to predict how many times an event will occur over the period of a year. I would like to approximate the probability of at least one event occurring from this output, though I am not sure how to go about it. I can get hold of the mean/base of the Poisson model very easily, which I'm guessing would be needed in any calculation.

Any help would be massively appreciated.

Thanks,

Skinicod.