This lesson is optional. It gives students the opportunity to put into practice what they have learned from this unit, but it may be safely skipped if there is a shortage of time.

In this lesson students practice finding conditional probabilities and independence of events after collecting their own data. Students write their own question, then collect data to support whether two events are independent or not. Then they examine another classic problem from statistics that has a solution that is not intuitive.
When students explain and justify how they determined probabilities, and ask each other questions, they are constructing viable arguments and critiquing the reasoning of others (MP3).