Different Kinds of Probability

By Jennifer VanBaren
These dice are both cubes and cuboids.
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Probability refers to the likelihood of something happening and appears in many subjects but especially math. There are several different kinds of probability including classical probability. Probability is often expressed as a ratio or with a colon in between the two numbers such as 5:10.

Classic Probability

The classical approach to probability often involves coin tossing or rolling dice. It is calculated by listing all of the possible outcomes of the activity and recording the actual occurrences. For example, if you are tossing a coin, the possible outcomes are either heads or tails. If you toss the coin 10 times, you record which outcome occurred each time you tossed the coin.

Experimental Probability

Experimental probability is based on the number of possible outcomes by the total number of trials. When tossing a coin, the total possible outcomes are two, heads and tails. The total number of trials is determined by the total times the coin is flipped. If the coin is flipped 50 times and it lands on heads 28 times, then the theoretical probability is 28/50.

Theoretical Probability

Theoretical probability is an approach that bases the possible probability on the possible chances of something happen. For example, if you want to know the theoretical probability that a die will land on a number "3" when rolled, you must determine how many possible outcomes there are. On a die, there are six numbers, offering six possibilities. To land on a three, you have a one-in-six, or 1:6, chance of it landing on a "3".

Subjective Probability

Subjective probability is based on a person's own personal reasoning and judgment. It is the probability that the outcome a person is expecting will actually occur. There are no formal calculations for subjective probability but instead it is based on a person's own knowledge and feelings. For example, during a sport's game, a fan of one team may state that the team they are rooting for will win. The person bases his decision on facts or opinions regarding the game, the two teams and the likelihood of the team winning.