A song about the fit of linear regression, describing the difference between observed and fitted values and related aspects. May be sung to the tune of "Mexican Hat Dance" (traditional). Recorded June 26, 2009 at the OSU Whisper Room: Larry Lesser, vocals/guitar; Justin Slauson, engineer. This song is part of an NSF-funded library of interactive songs that involved students creating responses to prompts that are then included in the lyrics (see www.causeweb.org/smiles for the interactive version of the song, a short reading covering the topic, and an assessment item).