Ms. Garcia Math
is the chance that an event will happen.
The easiest way to get the probability of a condition is to list all possible outcomes, and count the ones that fit the condition.
A tree diagram represents a sequence of events, showing all possible outcomes
From the tree diagram, we could count all of the possible outcomes.
The set of possible outcomes is: HH, HT, TH and TT
# possible outcomes = 4
Working out probabilies by counting
Once you have listed all possible outcomes, then you can work out the probabilities quite easily, counting the ones that fit the condition.
Example: What is the probability of flipping a coin 2 times and it coming up "heads" both times?
Answer: # of favorable outcomes = 1, # of possible outcomes = 4,
P(HH) = 1/4
if one event has
m possible outcomes
and a second independent event has
n possible outcome
s, then there are
m x n total possible outcomes
for the two events together.
Flip a coin and roll a die
There are 2 ways that you can flip a coin and 6 ways that you can roll a die. There are then
ways that you can flip a coin and roll a die.