Mathematics: Data Management and Probability
- compare, through investigation, the theoretical probability of an event with experimental probability, and explain why they might differ
- determine, through investigation, the tendency of experimental probability to approach theoretical probability as the number of trials in an experiment increases, using class-generated data and technology-based simulation models
Knowledge of basic Scratch menus, understanding of how to use of variables in Scratch coding, understanding of how to calculate percentages, knowledge of the concepts of experimental and theoretical probability.
These lessons provide opportunities for teachers and students to gather evidence through teacher, peer, and self-assessments; and learning goals and success criteria. See Growing Success: Assessment, Evaluation, and Reporting in Ontario Schools, Chapter 4 for more information.
Scratch desktop or mobile version
Whiteboard or chart paper
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This lesson will create a probability simulation that will demonstrate experimental and theoretical probabilities as well as the Law of Large Numbers.
Use the beginning portion of the following Brian Aspinall video, Coding a Coin Flipper.

Coding a Coin Flipper

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Students will:
  • Use their prior knowledge of probability to determine possible outcomes for stated events.
  • Create variables to store outcomes of simulation.
  • Use variables to determine experimental probability.
  • Create a turbo button to extend program to run multiple times.
  • Demonstrate how the more times you run the simulation the closer experimental comes to theoretical probability.
As a class:
  • review the use of variables.
  • What variables were used? List on the board or chart paper for everyone to refer to.
  • What was the purpose of each one?
  • Review procedure for calculating percent.
  • Students will use Scratch to code a probability simulator.
  • Students will assist each other in debugging their code in their own groups or with others in the classroom.
  • Students will document the percentage probability displayed by their simulator with four different sample sizes: 3, 5, 100, 1000.
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A gallery walk can occur so that students can see and try each other’s simulators. In a full group discussion, record and discuss the results of the various groups’ documentation. Students should use correct math terms.
Use of mixed ability groups would enable all to participate in coding discussions.
  • Ask students to consider what other probability simulators could be built, for example, die roller or spinner.
  • Ask students to consider what other math activities or algorithms could be automated in Scratch to teach concepts.
  • Use Scratch to code additional probability simulators.
  • Use Scratch to code additional math activities or algorithms.