Terms to Know Outcome: result of an action Event: A collection of possible outcomes Theoretical probability P(event)= number of favorable outcomes total number of possible outcomes

More words to Know Complement: P(A’): the collection of outcomes not contained in the event. P(A’)= 1- P(A) Ex: P(not heads)= 1 - P(heads) Experimental Probability P(event)= number of times an event occurs total number of trials

Making predictions I can use theoretical probability of an outcome to predict the number of times the outcome will occur in the future. I can use the experimental probability (relative frequency) of an outcome to predict the number of times the outcome will occur in the future.

More words to Know Relative Frequency: how often something happens divided by all outcomes It’s another word for experimental probability!!

Example of relative frequency We asked a class what kind of music the students like. 15 like pop music, 10 liked rock and roll, 4 liked hip hop or rap and 5 liked other kinds of music. Complete the table. Items Frequency Relative frequency Pop Music Rock and roll Hip-hop/rap other

Example of relative frequency We asked a class how many extra curricular activities they participate in. 15 said one, 10 said two, 5 said three, 1 said zero. Complete the table below. Items Frequency Relative frequency 1 2 3

Examples In the last hour a coffee shop sold twenty drinks including 8 lattes. If the shop sells ten drinks in the next hour predict how many will be lattes. Method 1 Method 2 Proportions Equivalent fractions

Examples According to the game rules, the probability that a bottled-water cap can be redeemed for a prize is 1/24. If a store stocks 500 bottles of water, about how many winning caps are likely? Method 1 Method 2 Proportions Equivalent fractions

Your Turn Suppose the probability that a bottle has a prize winning cap is only 1 out of 40. How many winning caps are likely among 500 bottles?

More examples Kayla flipped a coin 50 times. She recorded her results in the table. Predict the number of times the coin will land heads up, based on past trials, if she flips the coin 25o times. Side Number of Outcomes Relative frequency Heads 30 Tails 20

More examples Louis recorded the results of spinning a spinner 100 times. Next, he will spin the spinner 1,000 times. Predict the number of times the spinner will land on red. On green? On Yellow? Color Number of Outcomes Relative frequency Red 34 Yellow 20 Green 46

Question… Brandon Phillips batting average is 0.271. How many hits should we expect from him the next ten at bats? Batting Average = total # of hits total # of at bats