what is the parameter of the poisson distribution
Poisson distribution In probability theory and statistics, the Poisson distribution (French pronunciation [pwaˈsɔ̃]; in English often rendered /ˈpwɑːsɒn/), 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.[1] The Poisson distribution can also be used for the number of events in other specified intervals such as distance, area or volume.
Per mille A per mille[1][2][3] (from Latin per mÄ«lle, "in each thousand"[4]), also spelled per mil,[1][2][4][5][6][7][excessive citations] per mill,[4][5][6][7][8][9][excessive citations] permil,[4] permill,[4] or permille[3] is a sign indicating parts per thousand. Per mil should not be confused with parts per million (ppm).