Business Stat Lecture 3 01 26 2012 Experiments and random variables can be grouped into families where all random variables in family share a certain structure and particular random variable in a family is described by parameters X number of successes in n trials X is a Binomial random variable with parameters n p Permutations Pk n number of combinations of size k from group of n objects n n k order matters Combinations Ck n n n k k Order doesn t matter PMF probability mass function derivative of CDF cumulative distributive function CDF sum of PMFs Poisson family of random variables model for number of successes in experiment consisting of large number of independent trials with small probability of success for each trial Ex number of misprints in a book 01 26 2012 01 26 2012