Check out the clever and charming Dear Data project. The authors provide many examples of how multiple variables can be reported simultaneously in an appealing, comprehensible way.
If you can’t communicate the underlying relationships to your audience, it doesn’t matter how much you know about your data. Here are some well communicated, if not terribly important, depictions of common and separate sets.
In this era of fake news, it’s more important than ever to be able to tell whether opinion polling is legitimate. This class gives you tools to make such judgments. Check out this article at FiveThirtyEight about a recent poll, which may or may not have been real, that seemed to show significant support for a Kid Rock Senate bid.