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239 LearnersLast updated on November 24, 2025

Theoretical probability is a concept in statistics. It is used to calculate or analyze the likelihood of an event occurring. The calculations are done based on the known possible outcomes and mathematical principles. Here, the assumption is that all outcomes are equally likely. In this article, we’ll be learning about theoretical probability.
Theoretical probability is a way to predict how likely an event is to occur using mathematics rather than experiments. It assumes that all outcomes are equally probable. To find it, we divide the number of favorable outcomes by the total number of possible outcomes:
\(P(E) = \frac{\text{Number of favorable outcomes}}{\text{Total number of possible outcomes}} \)
It helps us understand the theoretical outcomes when they are known and predictable.
For example, if you roll a fair six-sided die, what is the probability of getting a 4?
Here,
Favorable outcome = 1
Possible outcomes = 6
So, the probability of getting 4 = \(1 \over 6\)
Therefore, the theoretical probability of rolling a 4 is \(1\over6\)
Probability is the way to measure how likely an event is to happen. The probability is always between 0 and 1. If the probability is 1, the event is sure to occur; if it is 0, the event cannot happen. There are two main types of probability: experimental and theoretical.
Theoretical probability is calculated using logic and known outcomes, while experimental and empirical probabilities rely on real-world trials and observed data, with empirical focusing on long-term observations.
| Theoretical Probability | Experimental Probability | Empirical Probability |
| Probability is based on reasoning, formulas, and known outcomes. | Probability is based on actual experiments or trials. | Probability is based on observed data collected from real-life and experiences. |
| Formula is: P(E) = Favorable outcomes divided by total possible outcomes. |
Formula is: P(E) = Number of times event occurs divided by total number of trials. |
Formula is: P(E) = Frequency of event divided by total observed frequencies. |
| Based on logic, models and mathematical rules. | Becomes more accurate with more trials. | Becomes more reliable with larger datasets. |
Theoretical Probability helps us predict how likely an event is to occur without doing any experiments. Theoretical Probability is the ratio of the number of favorable outcomes to the total number of possible outcomes. It is written as:
\(\text{Theoretical Probability} = \frac{\text{Favorable Outcomes}}{\text{Total Possible Outcomes}} \)
Theoretical probability tells us how likely an event is to happen by using theory instead of doing an experiment. To calculate it, follow these simple steps:
\(\text{Theoretical Probability} = \frac{\text{Favorable Outcomes}}{\text{Total Possible Outcomes}} \)
For example, a person owns 30 of 500 total raffle tickets. Find the probability of winning.
Here, the favorable outcomes = 30
Total possible outcomes = 500
p(winning) \(= {{30\over 500 }}= 0.06\)
The theoretical probability of winning the raffle is 0.06 or 6%.
Theoretical probability is used to understand the chances of an event occurring by reasoning rather than experimentation. Here are a few tips and tricks to master theoretical probability.
Memorize the formulas: Theoretical probability: \(P(E) = \frac{\text{Favorable outcomes}}{\text{Total outcomes}} \).
Remember that probability is always the number of favorable outcomes divided by the total number of possible outcomes.
Teachers can use real-life objects such as coins, dice, and cards to help students better understand theoretical probability.
Parents can help children understand theoretical probability by using everyday situations, such as predicting which fruit will be picked first from a bowl.
Students can use diagrams, such as tables or tree diagrams, to find outcomes more clearly.
When working on theoretical probability, students tend to make mistakes. Here, are some common mistakes and their solutions:
Theoretical probability is used in different fields to predict outcomes and make informed decisions. Here are some real-life applications of theoretical probability.
What is the probability of getting heads when tossing a fair coin?
The probability of getting heads is \(1\over 2\).
Identify the sample space:
S = {heads, tails}
Total outcomes = 2
Determine favorable outcomes:
Favorable outcome (heads) = 1
Calculate the probability:
P(heads) = \(1\over 2 \)
What is the probability of rolling a 4 on a fair six-sided die?
The probability of rolling a 4 is \(1 \over 6\) on a fair six-sided die.
Identify the sample space:
S = {1, 2, 3, 4, 5, 6}
Total outcomes = 6
Favorable outcome:
Only one outcome is 4.
Probability:
P(4) = \(1\over 6\)
What is the probability of drawing an Ace from a standard 52-card deck?
The probability of drawing an Ace is \(1\over 13\).
Total outcomes:
There are 52 cards
Favorable outcomes:
Number of aces = 4
Probability:
P(Ace) \(= {4\over 52} = {1\over 13}\)
What is the probability of obtaining a sum of 7 when rolling two fair six-sided dice?
The probability of obtaining a sum of 7 is \(1\over 6\).
Total outcomes:
\(6 \times 6 = 36\)
Favorable outcomes:
The pairs that sum to 7 are:
(1, 6), (2, 5), (3, 4), (4, 3), (5, 2), (6, 1) - 6 outcomes
Probability:
P(sum of 7) \(= {6\over 36 }= {1\over 6}\).
A spinner is divided into 8 equal sectors numbered 1 through 8. What is the probability of landing on sector 5?
The probability of landing on sector 5 is \(1\over 8\).
Total outcomes:
8 sectors
Favorable outcomes:
Only sector 5 qualifies
Probability:
P(5) \(= {{1\over 8}}\)
Jaipreet Kour Wazir is a data wizard with over 5 years of expertise in simplifying complex data concepts. From crunching numbers to crafting insightful visualizations, she turns raw data into compelling stories. Her journey from analytics to education ref
: She compares datasets to puzzle games—the more you play with them, the clearer the picture becomes!






