Example Question #1 : Simple Events
What is the probability of drawing an ace from a standard deck of fifty-two cards?
In order to solve this standard, we need to understand how to calculate the probability of simple events. A probability is generally defined as the chances or likelihood of an event occurring. It is calculated by identifying two components: the event and the sample space. The event is defined as the favorable outcome or success that we wish to observe. On the other hand, the sample space is defined as the set of all possible outcomes for the event. Mathematically we calculate probabilities by dividing the event by the sample space:
Let's use this information to solve our problem. We want to know the probability of drawing an ace from a deck of cards. We know that the sample space is fifty-two because there are fifty two cards or outcomes in the deck. Also, we know that there are only four aces in a fair deck of cards; therefore,
Now, let's convert this into a percentage:
Probabilities expressed in fraction form will have values between zero and one. One indicates that an event will definitely occur, while zero indicates that an event will not occur. Likewise, probabilities expressed as percentages possess values between zero and one hundred percent where probabilities closer to zero are unlikely to occur and those close to one hundred percent are more likely to occur.