Probability

Probability Terms: Experiment: an activity in which results are observed. Trial: each observation within an experiment. Outcome: each result in an experiment. Event: any set of one or more outcomes. Sample space: the set of all possible outcomes of an experiment EX: The sample space when rolling a die is 1, 2, 3, 4, 5, 6. An outcome would be rolling a 6. An event is what you’re finding the probability of…such as the probability of rolling a 1, 3, or 5.

Tomorrow will be Friday Probability is a measure of how probable it is that an event will occur. There will be a snow day tomorrow You will have homework tonight What other examples can you think of??? Pizza will be served for lunch today The sky will darken tonight Tomorrow will be Friday P = 1 P = 0 P = 0.25 P = 0.5 P = 0.75 It is not very likely it’ll happen. It might happen There is a strong chance it’ll happen It’ll definitely happen!!! It’ll NEVER happen!!!

Experimental Probability Data is collected through observations or experiments. Each result from the experiment is called an event. The probability of an event is equal to the number of times an event occurs divided by the total number of experiments. P (event) = Number of times an event occurs Total number of experiments

Experimental Probability P (event) = Number of times an event occurs Total number of experiments Event = scoring a basket 2 1 1 3 1 Number of baskets scored Number of shots taken

Theoretical Probability When you flip a coin there are When all possible events or outcomes are equally likely to occur, the theoretical probability can be found without collecting data from an experiment. Heads A penny has two sides When you flip a coin there are two possible outcomes or Tails P (event) = Number of favorable outcomes Total number of possible outcomes Heads Heads or Tails 1 2 = Tails Heads or Tails 1 2 =

Flip a coin 50 times!!! Heads Tails How many possible outcomes are there when flipping a coin? _________ What is the theoretical probability that you will get “heads “when flipping a coin? _________ Flip a coin 50 times!!! Record your results below Heads Tails What did you get for the experimental probability of getting heads? ________

If a die is rolled, how many possible outcomes are there? Rolling a Die If a die is rolled, how many possible outcomes are there? 6 What is the theoretical probability that you will throw a six? What is the theoretical probability that you will throw a two? What is the theoretical probability that you will throw a seven? What is the theoretical probability that you will throw an even number? 1 6 1 6 6 3 6 1 2

Odds Probability is the number of favorable outcomes over the total amount of outcomes. ODDS in favor are the number of favorable outcomes over the number of unfavorable or outcomes. ODDS against are the number of unfavorable outcomes over the number of favorable outcomes. EX: What are the odds in favor of drawing a 4 out of a deck of 52 cards? 4:48 = 1:12 What are the odds against drawing a 4 out of a deck of 52 cards? 48:4 = 12:1