Q. How to calculate Probability of event?

Ans.

What chance do I have to toss the coin and get a head? You might think 50-50, 50%. What about tossing it 5 times and getting a heads each time? The answer isn't as clear now. In order to answer this question, along with many others, it is important to be able to determine all of the possible outcomes.

Here is some vocabulary that will be used quite a bit in this course. Most of it should be familiar to you already.

Experiment: Any process that gives a result or observation.

Outcome: A particular result of an experiment.

Sample space: The set of all possible outcomes of an experiment. The sample space is typically called S and may be a list, a tree diagram, a chart, etc.

Sample points: Sample points are the individual outcomes in a sample. n(S) is the number of sample points in the sample space S. Just remember that none of the sample points can overlap and the sample space must contain all possible outcomes.

Event: Any subset of a sample space. If A is an event, then n(A) is the number of sample points that belong to event A.

The probability of an event occurring is:

The probability of event A occurring is denoted by P(A).