Sometimes a simple presentation can be the most effective. Effective conversations about data in the classroom are guided by specific norms. When participants abide by these norms, the conversation flows smoothly, and effective decisions can be made. When they don't abide by these norms, it can be impossible to conduct a conversation at all.
To teach this concept, I chose to use the analogy of traffic in a traffic circle (based on a recent bicycling experience). By juxtaposing a pair of images, showing how traffic works with and without drivers abiding by norms, I clearly demonstrated the importance of norms, and gave users a way to draw connections with their existing experiences.