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1216 LearnersLast updated on December 1, 2025

The activities or the events where the result is unknown are the experiments. A random experiment is an event or an activity where the outcome can be one or more and cannot be predictable. In this topic, we will learn more about random experiments, methods to analyze them, applications, and so on.
Probability theory itself is based on random experiments. Although the outcomes are unpredictable, random experiments are often repeated several times under the same conditions. A random experiment is part of the probability theory and the conditions to be fulfilled are:
Random experiments should be repeated several times under the same conditions
The outcome cannot be predicted in a random experiment.
Probability is a mathematical concept used to predict the likelihood of an event. It is calculated by comparing the number of ways an event can occur to the total number of possible outcomes. Follow the given steps to find the probability of random experiments.
Step 1: Identifying the Sample Space
The sample space is the possible outcomes of an experiment.
Step 2: Identify the Favorable Outcomes
Favorable outcomes are the outcomes that satisfy the event for which you want to calculate the probability.
Step 3: Use the Probability Formula
\({\text {Probability }}= {{{\text {Number of Favorable Outcomes }}\over {\text {Total Number of Possible Outcomes
}}}}\)
For example, what is the probability of getting exactly two heads when a coin is tossed twice?
When tossing a coin, the possible outcomes are heads or tails.
The possible outcomes when tossing a coin twice are: {HH, HT, TH, TT}
So, the total number of outcomes is 4.
Here, the favorable outcome is HH
So, the number of favorable outcomes = 1
So, the probability of getting exactly two heads is \(1\over 4\), or 0.25.
When learning probability, it is important to know and understand the terms related to random experiments. The terms used in a random experiment are outcome, sample space, and sample point.
| Terms | Meaning |
| Outcome | Outcome Outcomes are the possible results of a random experiment. For example, rolling a 4 when a die is thrown. |
| Sample space | The list or set of all possible outcomes of a random experiment. For example, for a die roll: S = {1, 2, 3, 4, 5, 6} |
| Event | A possible outcome or a group of outcomes. For example, getting an even number when rolling a die: {2, 4, 6} |
| Sample point |
Sample points are the individual elements of the sample space. For example, in a die roll, 1 or 6 is a sample space. |
| Trial | A trial is each repetition of a random experiment. For example, tossing a die 3 times means there are three trials. |


Understanding random experiments becomes easier when you break down the concepts into simple steps, practice regularly, and observe real-life situations where randomness occurs. Here are helpful tips for students to understand the idea of random experiments.
Mistakes are common among students when working on random experiments, mostly, they make the same errors. Take a look at some of the common mistakes and methods to avoid them, so that we can be wary of them.
In various fields in our daily lives, we use random experiments. Now, let’s learn some applications of random experiments.
What is the probability of getting an even number when a fair six-sided die is rolled?
The probability of an even number is \(1 \over 2\).
Even numbers in a six-sided die = 2, 4, and 6
Since there are 3 even numbers in six possible outcomes,
\({\text {Probability }}= {{{\text {Number of Favorable Outcomes }}\over {\text {Total Number of Possible Outcomes
}}}}\)
\(= {3\over 6 } = {1\over 2}
\)
A fair coin is tossed once. What is the probability of getting heads?
The probability of getting heads is \(1 \over 2\).
The possible outcomes: head and tail
The probability of getting heads = \(1 \over 2\).
A bag contains 3 red, 4 blue, and 5 green balls. A ball is picked randomly. What is the probability of picking a blue ball?
\(1 \over 3\) is the probability of picking up a blue ball.
Total number of balls = 12
The number of blue balls = 4
\({\text {Probability of Getting a Blue Ball }}= {{{\text {Number of Favorable Outcomes }}\over {\text {Total Number of Possible Outcomes
}}}}
\)
\(= {4\over 12 }
\\
\
\\
= {1\over 3}\)
A card is taken out from a deck of 52 cards. What is the probability of drawing a king?
The probability of drawing a king is \(1\over13\).
Total number of cards = 52 cards
The number of favorable outcomes = 4 cards
\({\text {Probability of Getting a King }}= {{{\text {Number of Favorable Outcomes }}\over {\text {Total Number of Possible Outcomes
}}}}\)
\(= {4\over 52 }
\)
\(= {{1\over 13}}\)
A number is randomly selected from 1 to 10. What is the probability of selecting a prime number?
The probability of choosing a prime number is \(2\over5\).
Total outcomes = 10
Favorable outcomes = 4 {2, 3, 5, 7}
Total numbers = 10
Prime numbers = 2, 3, 5, and 7
So, \({\text {Probability }}= {{{\text {Number of Favorable Outcomes }}\over {\text {Total Number of Possible Outcomes }}}}\)
\({= {4\over10} } \\
\
\
\\
{= {2\over 5}}\)
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!






