Average results per farm can be produced, but for any analysis produced there are always wide variations around average, which raises a number of issues:
Gellir cynhyrchu canlyniadau cyfartalog fesul fferm ond, ar gyfer unrhyw ddadansoddiad a gynhyrchir, mae amrywiadau eang bob amser amgylch cyfartaledd, sy'n codi nifer o faterion: