Lesson objective: Calculate the experimental probability based on data collected from an experiment on a spinner.

This lesson helps to build procedural skill with calculating experimental probabilities. Fractions are used here because they clearly represent the ratio of observed occurrences to total number of observations. This work develops students' understanding that they can use probabilities to generate hypotheses about the likelihood of an event.

Students engage in Mathematical Practice 4 (Model with mathematics) as they calculate probabilities as ratios to represent the results of an experiment.

**Key vocabulary:**

- experimental probability
- observed occurrences
- observations

**Special materials needed:**

- paper clips
- printed spinners (available on the last page of in-class practice)