As the study did not mention randomly selecting 2nd-graders of similar math levels to begin with, it is an observational study using inferential techniques. There are several possible explanations that piano lessons could improve a student’s math ability in fractions and proportions. 1. Piano keys are separated and yet grouped together which may improve a student's sense of fractions and proportions. 2. Music has rhythm and beats, each note (long or short) is part of a whole, this resembles math problems of fractions and proportions. 3. While playing a piano, a student uses a sheet music or imagines one in his or her head, the structure of a sheet music contains multiple lines which divide the different regions of notes both vertically and horizontally. This may improve a student's visualization and understanding of fractions and proportions.