9-6 Theoretical and Experimental Probability

Find and compare experimental and theoretical probabilities

Use a graphing calculator to complete the table

1 2 3 4 5 6

Times occurred

Probability using your results

What should the probability have been?

Create definitions for theoretical and experimental probability. Fill it

into a t-table

• Suppose you have a bag with 75 marbles: 15 red, 5 white, 25 green, 20 black, and 10 blue. You draw a marble, note its color, and then put it back. You do this 75 times with these results: 12 red, 9 white, 27 green, 17 black, and 10 blue. Find each probability as a fraction in simplest form.

P(red) P(white) P(green) P(black) P(blue)

Experimental probability

Theoretical probability

Suppose you surveyed the students in your class on their favorite juice flavors. Their choices were 6 apple, 10 orange, 1 grapefruit, and 3 mango. Find each probability as a fraction in simplest form.

1. P(apple)

2. P(orange)

3. P(grapefruit)

4. P(not mango)

Ex.) Two number cubes are rolled seventy-five times and a sum of 9 is

rolled ten times.

What is the experimental probability of rolling a sum of 9?

Do example 2 and 3 on page 394

In a survey, 100 people were asked to name their favorite Independence Day side dishes. What is the experimental probability of macaroni salad being someone’s favorite

dish?

Side Dish Number of People

Potato salad 55

Green salad or vegetable

25

Macaroni salad 12

coleslaw 8

Suppose 250 people attend the city’s barbecue. How many be

expected to choose macaroni salad as their favorite side dish?

In a survey, 50 people were asked to pick which movie they would see this weekend. Twenty

chose Horror Story, 15 chose The Ink Well, 10 chose The Monkey House, and 5 chose Little Rabbit. What is the experimental probability of

someone wanting to see The Monkey House?

Suppose 300 people are expected to attend a movie theater this weekend to see one

of the four movies mentioned above. How many can be expected to see The Monkey

House.

Workbook 9-6

Venn Diagram

• Experimental vs. Theoretical Probability

p 395: 3-18