I would like to create a bar graph visualization that compares 2 data elements. One is an estimate of how long a process should run in seconds and the other is the actual run time in milliseconds. It should group and count the estimates and display the number of items that exceeded the estimate and by how much and the number that ran in a shorter time and by how much.

To clarify, there would be a bar for each estimated time (or perhaps the top 25). For each bar, I want to see how many were over the estimate, and how many were under, rounded to the nearest half second. These would be stacked bars so I can see how many were 1 second long, how many were 2 seconds long, how many were 1 second short, etc.