Please post your tag synonym suggestions as new answers in this thread, one answer per suggestion.  Upvote answers where you believe that the suggested tags should be made synonyms, and downvote answers where you believe the tags should remain separate.  Well upvoted suggestions will be eventually implemented by the moderators (and then the corresponding answers will be deleted).  


  [1]: http://meta.stats.stackexchange.com/questions/120/tag-rename-suggestions
  [2]: http://stats.stackexchange.com/questions/29918/multilevel-covariance-structure-and-more
  [3]: http://stats.stackexchange.com/tags/synonyms
  [4]: http://meta.stats.stackexchange.com/questions/1198/should-the-data-visualization-and-figure-tags-be-merged