What tool helps show the distribution of values for up to three binary or discrete variables?

The tool that effectively shows the distribution of values for up to three binary or discrete variables is known as Contingency Tables. These tables provide a structured format to summarize the relationship between different categorical variables, presenting them in a matrix format. Each cell in the table indicates the frequency count of occurrences for specific combinations of the variables.

In the context of analyzing multiple discrete variables, Contingency Tables allow users to observe patterns and intersections directly, making it easier to understand how the variables interact with one another. This is particularly useful for assessing relationships in data involving categories such as "Yes" or "No" responses, or any other discrete data that can be classified into distinct groups.

Other tools listed have specific applications: Frequency Tables focus on single variable frequency counts, Histograms illustrate the distribution of continuous data, and Scatter Plots represent the relationship between two continuous variables. None of these other options can effectively display the intersections of three binary or discrete variables in the same comprehensive way as Contingency Tables do.