This document provides tips and examples for calculating probabilities. It explains that probability is defined as the desired outcomes divided by the total possible outcomes. It also notes that "OR" means addition and "AND" means multiplication when calculating compound probabilities. Examples are provided for simple probabilities like rolling a 5 or 6 on a dice, and compound probabilities like the chance of choosing someone who likes vanilla ice cream and then someone who likes chocolate. The document concludes with an example of using a known probability to predict outcomes over many trials.

1. Tips
 #1 probability means
𝐷𝑒𝑠𝑖𝑟𝑒𝑑
𝑇𝑜𝑡𝑎𝑙
 #2 OR means addition
 #3 AND THEN means multiplication
 #4 If there are multiple events then you multiply

2. Simple Probability Example
 What is the probability of rolling a 5 or 6 on a dice?
Desired = 1 + 1 = 2

3. Simple Probability Example
 What is the probability of rolling a 5 or 6 on a dice?
Desired = 1 + 1 = 2 Total = 6

4. Simple Probability Example
 What is the probability of rolling a 5 or 6 on a dice?
Desired = 1 + 1 = 2 Total = 6 2
6

5. Simple Probability Example
 What is the probability of rolling a 5 or 6 on a dice?
Desired = 1 + 1 = 2 Total = 6 2
6
Simplify =
1
3

6. Compound Probability Example
Ice Cream Flavors # of people
Strawberry 3
Vanilla 6
Chocolate 4
Sherbet 2
What’s the probability of choosing someone who likes vanilla and then choosing
someone who likes chocolate?
First Event: Vanilla
6
15

7. Compound Probability Example
Ice Cream Flavors # of people
Strawberry 3
Vanilla 6
Chocolate 4
Sherbet 2
What’s the probability of choosing someone who likes vanilla and then choosing
someone who likes chocolate?
First Event: Vanilla
6
15
Second Event: Vanilla
4
15

8. Compound Probability Example
Ice Cream Flavors # of people
Strawberry 3
Vanilla 6
Chocolate 4
Sherbet 2
What’s the probability of choosing someone who likes vanilla and then choosing
someone who likes chocolate?
First Event: Vanilla
6
15
Second Event: Vanilla
4
15
6
15
x
4
15
=
24
225

9. Compound Probability Example
Ice Cream Flavors # of people
Strawberry 3
Vanilla 6
Chocolate 4
Sherbet 2
What’s the probability of choosing someone who likes vanilla and then choosing
someone who likes chocolate?
First Event: Vanilla
6
15
Second Event: Vanilla
4
15
6
15
x
4
15
=
24
225
Simplify by 3 =
8
75

10. Predictions Example
If I spin the spinner 360 times, how many times
would I land on an even number?
Find the probability Make a proportion
3
8
3
8
=
𝑋
360
Solve
X = 135 times

11. Predictions Example
If I spin the spinner 360 times, how many times
would I land on an even number?
Find the probability

12. Predictions Example
If I spin the spinner 360 times, how many times
would I land on an even number?
Find the probability
3
8

13. Predictions Example
If I spin the spinner 360 times, how many times
would I land on an even number?
Find the probability Make a proportion
3
8

14. Predictions Example
If I spin the spinner 360 times, how many times
would I land on an even number?
Find the probability Make a proportion
3
8
3
8
=
𝑋
360

15. Predictions Example
If I spin the spinner 360 times, how many times
would I land on an even number?
Find the probability Make a proportion
3
8
3
8
=
𝑋
360
Solve
X = 135 times