What is a probability of an event?

Answer 1

Lets first start by defining some terms:

Probability (P) in statistics is defined as the chance of an event occurring.

Probability experiment is a chance process that leads to results called outcomes.

An outcome is the result of a single trial of a probability experiment.

A sample set is the set of all possible outcomes of a probability experiment.

An event consists of a set of outcomes of a probability experiment. An event can be one outcome or more than one outcome. The event can be anything from flipping a coin, to rolling a die, to picking a card.

The probability of any event (E) is:

(# of outcomes in E) / (total # of outcomes in sample space)

For example: Find the probability a die is rolled and you get a 4?

We know that there are 6 possibilities when rolling a die. We can either rolled a 1, or a 2, or a 3, or a 4, or a 5, or a 6.

Using the equation above:

P(rolling a 4)= 1/6

The event in this case is rolling a 4.