Shodor Education Foundation
Shodor Interactivate: Lesson: Tree Diagrams and Probability
This lesson plan helps young scholars develop tree diagrams and figure probability of events based on diagrams. Lots of resources are available to support teachers and students at this website.
Oswego City School District
Regents Exam Prep Center: Tree Diagrams
This tutorial demonstrates how tree diagrams are constructed and shows how to calculate the probability of an event using a tree diagram. There are links to a lesson, practice page, and teacher resource pages with useful tips.