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## Using Probabilities to Make Fair Decisions

#### High School Statistics - HSS-MD.B.6

How to Use Probabilities to Make Fair Decisions? The measurement of the possibility of an event taking place is what we call probability. The majority of the cases in the world have a probability of happening. One area where probability is very extensively used is the weather forecast. A smaller probability indicates that the chances of an event taking place are very low. The higher the probability, the greater are the chances of the event occurring. Probability is even used to make a fair decision, but how can we use this concept to make a fair decision? A fair decision is one where the possibility of all events happening is equal or if the expected value of a random variable is zero. A case of fair decision is when a football coach has to choose a captain from the team. The situation of fairness will be if he considers everyone on the team for the position; this way the probability of each team member to become captain is equal. You have to divide the chances of an event happening by the total number of outcomes to calculate it the probability for all events is the same or not. A series of worksheets that run students through a wide variety of ways to calculate probabilities and then we help students interpret the data to decide what is fair or as close to equal as possible.

### Printable Worksheets And Lessons  #### Homework Sheets

Are the games and methods of choosing turns fair?

• Homework 1 - 3 friends are playing with dice. They decide to roll a die. If it lands on 1 then you win \$10. If it lands on 2 then you win \$15. If it lands on any other number, you lose \$25.
• Homework 2 - Two teams decided to play football. They want to decide who receives first. Mike and Steve are the team captains. So, they have two suggestions to decide who receives the ball. Decide whether the suggestions are fair ways to make the decision.

#### Practice Worksheets

Beware: There are a few loaded questions in here.

• Practice 1 - 3 friends are playing with dice. They decide to roll a die. If it lands on 1, then you win \$30. If it lands on 2, then you win \$35. If it lands on any other number, you lose \$5. Is this game fair?
• Practice 2 - Two teams decided to play volleyball. They want to decide who serves first. So, they have two suggestions that who starts first. Decide whether the suggestions are fair ways.

#### Math Skill Quizzes

I can't believe that people way in on these type of decisions on a daily basis.

• Quiz 1 - A local scout troop is having a cash raffle. Each ticket is \$10. \$2,000 is the grand prize. 2 prizes of \$50 will be given out as well. You find out that 1,000 will be sold. How much will the average ticket holder lose?