Lesson objective: Understand that the actual frequency of an event occurring is not expected to be exactly the same as the predicted frequency in a probability model.

Students bring prior knowledge of experimental and theoretical probability from 7.SP.C.5. This prior knowledge is extended to analyzing experimental results as students calculate and compare theoretical and experimental probabilities. A conceptual challenge students may encounter is expecting that experimental results will be the same as predicted results.

The concept is developed through work with ratios and percents, which allow students to compare results.

This work helps students deepen their understanding of equivalence because the experimental results approach the theoretical results as the number of observations increases.

Students engage in Mathematical Practice 4 (Model with mathematics) as they calculate theoretical and experimental probabilities and analyze the results. Students will take a real-world situation and make sense of it using a probability model.

**Key vocabulary:**

- experimental probability
- observations
- theoretical probability