If the probability of an event is 0.8, what is the probability of the event not occurring?

The probability of an event not occurring can be determined using the complementary probability rule. If the probability of an event occurring is given as 0.8, this means that the event will happen 80% of the time. The total probability of all possible outcomes must equal 1. Therefore, to find the probability of the event not occurring, you can subtract the probability of the event occurring from 1.

Mathematically, this is represented as:

Probability of not occurring = 1 - Probability of occurring

In this case:

Probability of not occurring = 1 - 0.8 = 0.2

This calculation confirms that the probability of the event not occurring is indeed 0.2, which aligns with the correct answer.