If you are rolling a die and want to see your chances of getting a 6, probability can help!
- A probability is the likelihood of a favorable or specific outcome happening.
- A probability of an event or Outcome always ranges from 0 to 1. The closer it is to 1, the more likely that event will occur.
- Here are a few terms to keep in mind:
- Sample Space or Total Outcomes: All possible results of an experiment are outcomes. If you are rolling a die, the total outcomes are 6. The sample space, in this case, is 6.
- Favorable Outcome (s): If you are looking for an even number, the total favorable outcomes are 3.
- Event: An event is a set of some favorable or all outcomes.
There are two categories of probability.
- Theoretical Probability
Theoretical or actual probability where all outcomes are equally likely is:
- Experimental Probability
Experimental probability is based on data collected from repeated trials or surveys.
1. What is the probability of getting 6 when you roll a die?
Total outcomes: 6
Favorable outcome(s): 1
P(Getting 6) =
2. You randomly pick a card from a deck of cards. What is the probability that it is of spade suite?
Total outcomes: 52 (52 cards in a deck)
Favorable outcome(s): 13 (13 spade cards)
- Probabilities are usually expressed in form.
- A probability of 0 means an event can't occur.
- A probability of 1 means the event is sure to occur.
- Even though the probability is usually expressed as a fraction, it can be expressed as a decimal or percent.