First decide whether the events are independent or mutually exclusive
- P(A or B)
- They are independent of one another. Multiply.
or
P(A
and B) They are dependent Mutually Exclusive.
1.
Adding=When you add events are more likely to happen. (There's a higher probability)
- Example: what is the chance of you getting a (5) or a (6) on two roll of the dice?
- The probability is
1/6 (+or) 1/6 =2/12 - .1666 (about a 17 percent chance it happens)
2.
Multiplying = when you multiply two events are less likely to happen (the probability goes down)
Example what is the probability of you getting a A Queen top and a King on the bottom of a stack of cards with two draw
4/52 (x and) 4/51 = 16/2652 = .006 (no probability)