To find the probability of the complement of an event, you can use the following formula:
P(not E) = 1 – P(E)
Given that the probability of event E is 0.31, we can substitute this value into the formula:
P(not E) = 1 – 0.31 = 0.69
Therefore, the probability of the complement of event E is 0.69. This means that there is a 69% chance that event E will not occur.