1. Bell Ringer 1. A sweater was on sale of $18.79. It originally cost $25.00. What is the percent of decrease of the sweater? 2. A flag pole stands 12 feet tall and casts a shadow 7 feet long. A garbage can is 4 feet tall. What is the length of the garbage can’s shadow?

2. Probability

3. Probability Probability: how likely it is that something will occur P(event) Probability: how likely it is that something will occur P(event) Outcome: the result of a single trial Outcome: the result of a single trial Event: any outcome or group of outcomes Event: any outcome or group of outcomes Sample Space: all the possible outcomes Sample Space: all the possible outcomes

4. Theoretical Probability P(event)= EX) P(rolling an even #)= 3/6 = ½ EX) P(tail) = ½ EX) P(rolling a 2)= 1/6 # of favorable outcomes # of possible outcomes

5. Compliment of an Event EX) A contestant must choose one of five envelopes in which one contains the grand prize, a car. Find the probability of not choosing the car. P(car) = 1/5 P(not choosing the car) = 1 – P(car) = 1 – 1/5 = 1 – 1/5 = 4/5 = 4/5

6. Experimental Probability P(event)= EX) A skateboard manufacturer inspected 1000 skateboards at random and found no defects in 992 skateboards. What is the probability that a skateboard selected at random had no defects? P(no defects) = 992/1000 = 99.2% # of times an event occurs # of times the experiment is done