It is also called the rate parameter.įor instance, on a particular river, overflow floods occur once every 100 years on average. History of The Normal Distribution PDF and CDF of The Normal Distribution Calculating the Probability of The Normal Distribution using Python References 1. Where lambda is a parameter which equals the average number of events per interval. Normal distribution calculator finds cumulative normal probabilities and z-scores. Probability density function of the poisson distribution is The calculator will generate a step by step explanation along with the graphic representation of the area you want to find. The Poisson distribution can also be used for the number of events in other specified intervals such as distance, area, or volume. Enter mean, standard deviation and cutoff points and this calculator will find the area under normal distribution curve. In probability theory and statistics, the Poisson distribution, named after French mathematician Siméon Denis Poisson, is a discrete probability distribution that expresses the probability of a given number of events occurring in a fixed interval of time or space if these events occur with a known constant rate and independently of the time since the last event.