POISSON.DIST(x,mean,cumulative)
=POISSON.DIST(3, 2, FALSE)
In this example, the POISSON function is used to calculate the probability mass function (PMF) of a Poisson distribution with a mean of 2 for observing exactly 3 events. The formula returns the probability of observing exactly 3 events in a fixed interval when the average number of events in that interval is 2. The third argument, FALSE, specifies that we want to calculate the PMF, not the cumulative distribution function (CDF).
=POISSON.DIST(4, 3, TRUE)
In this example, the POISSON function is used to calculate the cumulative distribution function (CDF) of a Poisson distribution with a mean of 3 for observing 4 or fewer events. The formula returns the probability of observing 4 or fewer events in a fixed interval when the average number of events in that interval is 3. The third argument, TRUE, specifies that we want to calculate the CDF, not the probability mass function (PMF).
The POISSON.DIST function calculates the Poisson distribution, used to predict the number of events within a specific time. It requires three arguments: X, mean, and cumulative.