We don't need a whole lot of facts about probabilities in this course. The following will do:
Every probability is between 0 and 1, inclusive.
The sum of the probabilities of all possible events must be 1.0
If p is the probability that an event will happen, then (1-p) is the probability that the event will not happen.
If two events are independent and occur with probabilities p_{1} and p_{2}, respectively, then the probability that both events will occur is p_{1}*p_{2}
If we make a number of independent attempts at something, and the chance of seeing an event on any single attempt is p, on average we will need 1/p attempts before seeing that event.
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