So..You’re Saying There’s a Chance?
What is the chance of rolling snake eyes with dice or pulling the Ace of Spades from a deck of cards? These chances are known as probability. To determine probability, you have to set up a controlled environment that is repeatable known as an experiment. The set of all possible outcomes is the sample space. The set of possible outcomes for which probability has been assigned is known as an event. Events can be certain or impossible. For example, it is certain that time will keep moving forward, but impossible that time will move backwards. In games of chance, an event is a die landing with 5 facing up when that is the desired outcome.
May the Odds Be in Your Favor
To determine probability, we use the formula:
When setting up a problem, “probability of an event” is shortened to p(A). The A is a stand-in for whatever the question is asking. For example, if you have a quad-colored spinner wheel and want to know the probability of the spinner landing on blue, you would set up the problem as:
Probabilities can be written as fractions, percents, or ratios. A certain probability is written as 1 as there is a 100% chance the event will happen. An impossible event is written as 0 as there is 0% the event will happen. In the case of the quad-colored spinner wheel, there is a 1 in 4 chance that the spinner will land on blue. It can be written as 1/4, 25%, or 1:4.
