adambard/learnxinyminutes-docs — pull request #843 by brunokim (2014-11-01 03:38:04+00:00)
Title: Remove misleading example of NA in Levels section

The levels section was using a level "NA" together with "female" and "male", which is misleading (given that NA was just introduced as a missing value). I updated it to what I believe is a better example of how NAs are interpreted.

Additionally, I edited a comment about Inf that wouldn't compile. How about inserting it at the tutorial altogether?