Clarifications
Clarification 1: Instruction includes representing probability as a fraction, percentage or decimal.Clarification 2: Simple experiments include tossing a fair coin, rolling a fair die, picking a card randomly from a deck, picking marbles randomly from a bag and spinning a fair spinner.
Benchmark Instructional Guide
Connecting Benchmarks/Horizontal Alignment
Terms from the K-12 Glossary
- Event
- Theoretical Probability
Vertical Alignment
Previous Benchmarks
Next Benchmarks
Purpose and Instructional Strategies
In grade 7, students find the theoretical probability of an event related to a simple experiment, and in grade 8, they will find the theoretical probability of an event related to a repeated experiment.- Instruction builds on finding sample spaces from MA.7.DP.2.1. Have students discuss their understanding of the words “theoretical” and “probability” to build toward a formal definition of theoretical probability.
- When finding theoretical probability, have students work from their sample space. Doing so will lead to the understanding that since experiments for this benchmark are fair, the probability of an event is equivalent to .
- For example, if rolling a fair 6-sided die, the sample space is {1, 2, 3, 4, 5, 6,}. If one wants to find (), students can circle all of the odd numbers from the sample space to determine the probability as , or 0.5.
- While the benchmark does focus on fair experiments, instruction could include spinners with unequal sections making the connection to angle measures and to circle graphs.
- Instruction focuses on the simple experiments listed in Clarification 2.
- For example, when tossing a coin with one side colored yellow and the other side colored red, () = 0.
- For example, when rolling a 10-sided die, ( 3) = 0.7.
- For example, when picking a card from a deck that contains each of the letters of the alphabet, () = .
- For example, when picking a tiles from a bag that contains a set of chess pieces, () = 50%.
- For example, when spinning a spinner that contains 5 sections where two of the sections are green and the remaining sections are red, white and blue,
() = .
Common Misconceptions or Errors
- Students may incorrectly convert forms of probability between fractions and percentages. To address this misconception, scaffold with more familiar values initially to facilitate the interpretation.
- Students may incorrectly count outcomes when one outcome appears more than once in the sample space.
- For example, if the sample space is {red, red, blue} and one wants to find (), a student may incorrectly state or instead of .
Strategies to Support Tiered Instruction
- Teacher provides instruction in converting between fractions and percentages, by using more familiar values.
- For example, = 50%, = 25%, ≈ 33.3%, etc.
- Teacher co-creates a T-chart (like the one below) to list the experiment and the sample space necessary for the examples provided.
Instructional Tasks
Instructional Task 1 (MTR.4.1, MTR.7.1)Look at the shirt you are wearing today and determine how many buttons it has. Then complete the following table for all the members of your class.
- Part A. What is the probability that the student whose card is selected is wearing a shirt with no buttons?
- Part B. What is the probability that the student whose card is selected is female and is wearing a shirt with two or fewer buttons?
Instructional Task 2 (MTR.4.1, MTR.5.1)
There is only one question on the next quiz and it will be true or false.
- Part A. If a student randomly answers the question, what is the probability of earning a score of 100%?
- Part B. What is the probability of earning a 50%?
Instructional Items
Instructional Item 1What is the probability of choosing a 9 from a standard deck of 52 cards?
Instructional Item 2
There are 7 red, 5 blue and 12 green marbles in a bag.
- Part A. What is the probability of choosing a red marble?
- Part B. What is the probability of not choosing a green marble?
- Part C. What is the probability of choosing a yellow marble?
- Part D. What is the probability of choosing a red or blue marble?
*The strategies, tasks and items included in the B1G-M are examples and should not be considered comprehensive.
Related Courses
Related Access Points
Related Resources
Formative Assessments
Lesson Plans
Perspectives Video: Expert
Problem-Solving Tasks
Text Resource
Tutorials
MFAS Formative Assessments
Students are asked to estimate the frequency of an event given its probability and explain why an expected frequency might differ from an observed frequency.
Students are given a scenario and asked to determine the probability of two different events.
Student Resources
Problem-Solving Tasks
This resource involves a simple data-gathering activity which furnishes data that students organize into a table. They are then asked to refer to the data and determine the probability of various outcomes.
Type: Problem-Solving Task
The purpose of this task is for students to compute the theoretical probability of a seating configuration. There are 24 possible configurations of the four friends at the table in this problem. Students could draw all 24 configurations to solve the problem but this is time consuming and so they should be encouraged to look for a more systematic method.
Type: Problem-Solving Task
Tutorials
This video demonstrates several examples of finding probability of random events.
Type: Tutorial
This video demonstrates how to find the probability of a simple event.
Type: Tutorial
Parent Resources
Problem-Solving Tasks
This resource involves a simple data-gathering activity which furnishes data that students organize into a table. They are then asked to refer to the data and determine the probability of various outcomes.
Type: Problem-Solving Task
The purpose of this task is for students to compute the theoretical probability of a seating configuration. There are 24 possible configurations of the four friends at the table in this problem. Students could draw all 24 configurations to solve the problem but this is time consuming and so they should be encouraged to look for a more systematic method.
Type: Problem-Solving Task