**Binomial Probability Distribution**

Only two outcomes – fixed number of trials – independent events

,

Where: is the probability of success, is the probability of failure and is the number of trials.

and

**Bernoulli Probability Distribution**

Only two outcomes 0 and 1.

,

Where: is the probability of success, is the probability of failure.

**Geometric Probability Distribution**

Number of trials until FIRTS SUCCESS.

Where: is the probability of success and is the probability of failure.

**Negative Binomial Probability Distribution**

How many trials for successes. I.e. number of trials where 2nd, 3rd etc. success will occur.

,

Where: is the probability of success, is the probability of failure and is the numer of successes.

**Hypergeometric Probability Distribution**

Conditional probability of a selection. Thus trials are not independent.

E.g. Bag with 4 red and 7 green tokens, thus . Randomly select **without replacement**. Number of red tokens . Probability of selecting 1 red:

**Poisson Probability Distribution**

Number of successes in a time interval.

is the mean number of successes per interval. .

The Poisson probability distribution can be used to approximate the binomial probability distribution for large and small .