A song for use in discussing the interpretation of the root mean squared error – or the standard deviation of the residuals. The lyrics were written by Mary McLellan from Aledo High School in Aledo, Texas as one of several dozen songs created for her AP statistics course. The song may to be sung to the tune of Michael Jackson’s 1982 hit song “Billy Jean.” Also, an accompanying video may be found at https://www.youtube.com/watch?v=RW-Rfn86CSQ