C.3 Section 2.6-2.7 WHAT IS PROBABILITY? Probability : is the likelihood of an event occurring. It can be expressed as a fraction, decimal or percent. Probability for event is

Range of Possible Probabilities Less likely More likely .5 50% ½ 1 Equally Likely and Unlikely Impossible Event Certain Event Rolling a 7 on a number cube Rolling a number less than 7 on a number cube Getting a head when flipping a coin

Ex. 1 – Rolling a Standard Number Cube Find Ex. 2 Ex. 3

A jar contains 15 blue marbles, 10 red, 5 green and 5 yellow. Ex. 4 Ex.5 Ex. 6

Probability with Standard Deck of Cards A card is selected at random from a standard deck of 52 cards. What is the Probability of selecting a 3? A card is selected at random from a standard deck of 52 cards. What is the Probability of selecting a 2 or a 5?

Probability with Standard Deck of Cards A card is selected at random from a standard deck of 52 cards. What is the Probability of selecting a Face Card? A card is selected at random from a standard deck of 52 cards. What is the Probability of selecting a Spade?

Experimental Probability Quality control inspected 500 belts at random. They found no defects in 485 belts. What is the probability that a belt selected at random will pass quality control?

Now You Try Find each probability for the roll of a number cube. 1. P(4) 2. P(not 4) 3. P(odd) 4. You spin the following spinner. P(red) b) P(a number less than 6) c) P(a number greater than or equal to 6) d) P(Not a multiple of 3)

Extending the Idea of Probability Suppose you roll a number cube 60 times. How many times should you get a 5? Suppose you spin the following spinner 100 times, how many times should you get a 6?

Extending Ideas of Probability Using the spinner at the left, answer the following questions. Give an example of a certain event. Give an example of an impossible event.