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# Probability Calculator

## How to use the probability calculator?

• Enter the number of events that occurred n(E).
• Enter the number of possible outcomes n(T).
• Click the “calculate” button.
• Use the reset button to enter new values.

## Probability calculator

Probability calculator evaluates the probability of occurring events out of total number of possible outcomes. This event probability calculator finds single-event probability. For example; a coin is tossed 90 times and we have to calculate the chances of occurring head in the 1st five times.

## What is probability?

Probability is simply how likely something is to happen. It is the outcome of a random event i.e. if we toss a coin we cannot say what will be the result whether it will be head or tail until the event happens. The probability ranges between 0 and 1.

If the probability of an event is 0.6 then it means there is a 60% chance of happening that event. The probability theory contains some sub-terms in it, to understand the concept of probability first we have to go through these basic terms.

• Experiment: To find well-defined outcomes we do experiments.
• Trial: The term “trial” represents how many times an experiment is performed.
• Outcome: It is the possible result.
• Sample space: All the possible results together make a sample space. It is represented by curly brackets {}.
• Event: The sample space is a set, and all of its subsets are known as events.

### The formula of probability:

The general formula to calculate the single event probability is as follows:

Probability = number of events occurred n(E) / number of possible outcomes n(T)

### How to calculate probability?

We can calculate the probability of a sample space by following the below steps.

• Check the number of all possible outcomes n(T)
• Find out the number of events that occurred n(E)
• Divide n(E) by n(T)

To understand the method more precisely, have a look at the following examples.

Example 1:

A fair die is rolled one time, what are the chances of coming the face 6?

Solution:

Step 1: Check the number of all possible outcomes n(T)

A die has six faces so n(T) = 6

Step 2: Find out the number of events that occurred n(E)

The die is rolled one time so n(E) = 1

Step 3: Calculation

Probability = n(E) / n(T)

Probability = 1/6

Probability = 0.1667

Probability = 16.67%