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Basic terms on probability:
Now we learn about some basic terms on probability. That is,
- Random experiment or trial.
- Outcome.
- Sample point.
- Sample space.
- Event.
1. Random experiment or trial:
A trial is an action which results in one or several outcomes.
Example:
Rolling dice and tossing a coin are trials.
2. Outcome:
The results obtained after the performance of the trial or experiment or operation is called an outcome.
Example:
1) While flipping a coin, we get head or tail. Head and tail are called outcomes.
2) When we are rolling a die, there are \(6\) certain probability results in \(1\), \(2\), \(3\), \(4\), \(5\), \(6\) which are called outcomes.
3. Sample point:
Each outcome of a random experiment is called a sample point.
While flipping a coin, each outcome \(H\) or \(T\) is the sample points.
4. Sample space:
The set of all possible outcomes (or sample points) of a random experiment is called the sample space.
In a single flip of a coin, the collection of sample points is given by \(S =\) \({H, T}\).
If two coins are tossed the collection of sample points \(S = {(HH),(HT),(TH),(TT)}\).
It is denoted by \(S\). The number of elements in it is denoted by \(n(S)\).
5. Event:
Any subset of a sample space is called an event.
If a dice is rolled, it shows \(4\), which is called an outcome (since it is a result of a single trial).
Even denoted as \(E\) and the number of events is denoted as \(n(E)\) which is nothing but the total number of events.
In the same experiment, the event of getting an even number is \({2,4,6}\).
Therefore here the total number of events \(n(E) = 3\).
Hence an event can be one or more than one outcome.
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