What does the probability of \[1\] mean?

Hint: Probability is the chance that something will happen. The probability of an event is the likelihood of that event occurring. Probability is a value between (and including) zero and one. Probability is the branch of mathematics that deals with the likelihood of occurrence of an event.

Complete answer:
The probability of an event occurring is somewhere between impossible and certain. As well as words, we can use numbers to show the probability of something happening:
(1) Impossible is zero
(2) Certain is one

The probability of \[1\] means the event is certain to happen, i.e. the event is a sure event.That means, the event will definitely occur. For example, the probability of getting a number greater than \[0\] on throwing a die is \[1\] since it is a sure event.

The probability of an impossible event is \[0\]. For example, the probability of getting a number greater than \[6\] on throwing a die is \[0\] since it is an impossible event. Also, the sum of all the probabilities of a random experiment is equal to \[1\]. The sum of probability of an event and its complementary event is \[1\].

Note: If P(E) represents the probability of an event E, then \[0\]≤ P(E) ≤\[1\]. An event with a higher probability is more likely to occur than one with a lower probability. The probability of an event will not be less than \[0\]. This is because \[0\] is impossible (sure that something will not happen). The probability of an event will not be more than \[1\]. This is because \[1\] is certain that something will happen.