Mathematics for IGCSE & O level - Probability (Section 3 - No. 1)
Two events are considered independent if:
The outcome of the second event affects the outcome of the first.
The outcome of the first event affects the outcome of the second.
The outcome of the second event is not affected by the outcome of the first.
The events are mutually exclusive.
Explication
Independent events are those where the outcome of one does not influence the outcome of the other.