Really—nothing too challenging. While the data exercise wasn't particularly difficult, I did notice one question that could easily trip someone up if they weren't being entirely thorough during their data cleaning. My advise: take your time and really look over your results; avoid answers that are correct but somewhat sloppy or hurried. Also, take the time to return your results in a clean format and include the script. This will likely help your chances big time.
Sigiloso
The data exercise basically consisted of reading in and cleaning some data, then providing some basic summaries. This required some regular expressions, sorts, subsets, joins/merges, summary/group bys.