An event that is certain<span> to happen has a probability of 1(So yes an event can have a probability of 1). An event that cannot possibly happen has a probability of zero. (examples below) </span><span>--If it is Thursday, the probability that tomorrow is Friday is certain, therefore the probability is 1. --If you are sixteen, the probability of you turning seventeen on your next birthday is 1. It's a certain event. </span>
