1. Definitions Probability is the mathematics of chance. It tells us the relative frequency with which we can expect an event to occur The greater the probability the more likely the event will occur. It can be written as a fraction, decimal, percent, or ratio.

2. Definitions Certain Impossible.5 1 0 50/50 Probability is the numerical measure of the likelihood that the event will occur. Value is between 0 and 1. Sum of the probabilities of all events is 1.

3. Definitions There are three types of probability 1. Theoretical Probability Theoretical probability is used when each outcome in a sample space is equally likely to occur. P(E) = Number of Event Outcomes Total Number of Possible Outcomes in S The Ultimate probability formula

4. Definitions There are three types of probability 2. Experimental Probability Experimental probability is based upon observations obtained from probability experiments. The experimental probability of an event E is the relative frequency of event E P(E) = Number of Event Occurrences Total Number of Observations

5. Definitions There are three types of probability 3. Subjective Probability Subjective probability is a probability measure resulting from intuition, educated guesses, and estimates. Therefore, there is no formula to calculate it. Usually found by consulting an expert.

6. Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 3 or 5?

7. A bag contains 2 red, 3 green and 4 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue?

8. In a box, there are 8 red, 7 blue and 6 green balls. One ball is picked up randomly. What is the probability that it is neither red nor green?

9. The diagram shows a spinner made up of a piece of card in the shape of a regular pentagon, with a toothpick pushed through its center. The five triangles are numbered from 1 to 5. The spinner is spun until it lands on one of the five edges of the pentagon. What is the probability that the number it lands on is odd?

10. Each of the letters of the word MISSISSIPPI are written on separate pieces of paper that are then folded, put in a hat, and mixed thoroughly. One piece of paper is chosen (without looking) from the hat. What is the probability it is an I?

11. A card is chosen at random from a deck of 52 playing cards. There are 4 Queens and 4 Kings in a deck of playing cards. What is the probability it is a Queen or a King?

12. If there are six horses in a race and each horse has an equal chance of winning, what is the probability of you picking the top three finishers in perfect order?

13. A fair coin is tossed three times. What is the probability of obtaining one Head and two Tails? (A fair coin is one that is not loaded, so there is an equal chance of it landing Heads up or Tails up.)