Lesson objective: Understand that we can design simulations to generate frequencies for compound events, and then compare the observed frequencies to the expected frequencies.

Students bring prior knowledge of experimental probability from 7.SP.7. This prior knowledge is extended to compound events as students design simulations to generate frequencies for compound events. A conceptual challenge students may encounter is understanding that the ratios of outcomes of a model must be equivalent to the ratio of the outcomes of the situation.

The concept is developed through work with a comparison of ratios, which helps determine if a method for simulation will accurately model a given situation.

This work helps students deepen their understanding of equivalence because comparisons of ratios will be made to determine if they are equivalent and can be used to model a situation.

Students engage in Mathematical Practice 5 (use appropriate tools strategically) as they compare models and determine if the ratios of the outcomes will model the given situation.

**Key vocabulary:**

- expected frequency
- experimental probability
- observed frequency
- relative frequency
- simulation
- theoretical probability

**Special materials needed:**

- calculator
- colored chips
- colored cubes
- colored marbles
- coins
- deck of cards
- number cubes
- spinners
- tickets