Unit 4: Probability

Day 2: Basic Probability

Standards and Benchmarks

9.4.3.1 Select and apply counting procedures, such as the multiplication and addition principles and tree diagrams, to determine the size of a sample space (the number of possible outcomes) and to calculate probabilities.

Learning Targetsa) I can apply multiplication principles to determine the number of possible outcomes in a sample space.b) I can apply the addition principle to determine the number of possible outcomes in a sample space.c) I can apply tree diagrams to determine the number of possible outcomes in a sample space.d) I can calculate the probability of an event.

Basic ProbabilityProbability is the measure of how likely an event is to

occur. Each possible result of a probability experiment or situation is an outcome. The sample space is the set of all possible outcomes. An event is an outcome or set of outcomes.

Basic ProbabilityEqually likely outcomes have the same chance of

occurring. When you toss a fair coin, heads and tails are equally likely outcomes. Favorable outcomes are outcomes in a specified event.

Basic ProbabilityYou can estimate the probability of an event by using data,

or by experiment. For example, if a doctor states that an operation “has an 80% probability of success,” 80% is an estimate of probability based on similar case histories.

Each repetition of an experiment is a trial. The sample space of an experiment is the set of all possible outcomes.

Basic ProbabilityCompare the experimental probability of getting heads or

tails on a coin toss to the theoretical probabilityExperiment: 1) Each student will toss a coin 50 times. Keep track of the

results (ie. How many times did tails come up, how many times did heads come up)

2) Gather class data and calculate the experimental probability of heads and tails.

3) Compare to the theoretical probability of heads and tails.

Basic Probability

Another common activity is rolling 2 dice.How big is the sample space?What is the sample space (possible

outcomes)?

Basic ProbabilitySample space for rolling two dice

What is the probability of getting a sum of 7?

What is the probability of getting a pair?

What is the probability of getting a sum of 13?

Basic Probability

Work Time:WKST: Problem Solving 1 (11-2) Problem Solving 2 (10-5) Puzzles Twisters and Teasers

Basic Probability

Exit quizFind the probability of each event when two dice are rolled1) P (sum of 5) =

2) P (sum greater than 10) =

3) P (doubles) =

4) P (sum is even) =