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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.