Everything you need to know about in grade 6 Probability

(The chance of something happening) Probability (The chance of something happening) Certain (100% sure it will happen) Likely (Large chance it will happen) Possible (It may or may not happen) Unlikely (Small chance it will happen) Impossible (100% sure it will not happen)

There are 2 kinds of probability experimental probability theoretical probability

Experimental Probability (Based on the results of an experiment) For example: When rolling a die five times, what is the experimental probability of getting a six? So, in this case… the experimental probability of getting a six is 2 or 40% 5 Out of my 5 tests, I rolled a six twice

Theoretical Probability (Based on all the possible outcomes) So… The theoretical probability of getting a six is 1 6 For example: When rolling a die, what is the theoretical probability of getting a six? Rolling a 6 is one out of six possible outcomes

Theoretical Probability We can also determine all possible outcomes in situations with multiple factors.

When I go out for dinner with my family, I get to order an For example: When I go out for dinner with my family, I get to order an appetizer, main dish, and dessert. The appetizers on tonight‘s menu are garden salad or mushroom soup. The main dishes are beef stew, lasagna, or grilled chicken. The desserts are fruit salad or sorbet. List all the possible meal combinations.

I can lay out all my options in a TREE DIAGRAM I can follow the branches of my diagram to see all my possible combinations. I will list my appetizer options first. I can count the items in the right column to know the amount of choices I have. Next, I will list my main dish options. Last, I will list my dessert options. I count 12 possible choices. Fruit Salad Beef Stew Sorbet Garden Salad Fruit Salad Lasagna Sorbet Grilled Chicken Fruit Salad Sorbet Fruit Salad Beef Stew Sorbet Mushroom Soup Fruit Salad Lasagna Sorbet Grilled Chicken Fruit Salad Sorbet

There are 12 possible choices If all I wanted to know was how many possible combinations there were, I could have created a table I could then multiply together the amount of choices in each category to determine the total number of possible combinations 2 x 3 x 2 = 12 There are 12 possible choices 2 choices X 3 choices X 2 choices Appetizers Main Dishes Desserts Garden Salad Beef Stew Fruit Salad Mushroom Soup Lasagna Sorbet Grilled Chicken

Let’s see if you can answer some probability questions… Sam actually only got heads once Did he do anything wrong? If Sam flipped a coin ten times, how many times would you expect him to get heads? No he didn’t! Experimental probability can be different from theoretical probability. Even though it is unlikely that Sam would only get heads once, it is still possible. Right! You would expect him to get heads 5 times, because the theoretical probability of getting heads is 1/2 and 5/10 = 1/2

8/25 or 32% Let’s see if you can answer some probability questions… We surveyed our class to find out about ice cream preferences. 12 preferred vanilla 8 preferred chocolate 5 didn’t like ice cream at all. Each student writes his/her name on a slip of paper and puts it in a bag. What are the chances of drawing the name of a student who prefers chocolate ice cream? 8/25 or 32%

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