population regression function, or population regression ( PR ) for short; indicate the equation E(Y|X)=f(x)=a+bx.
PRF
Meaning of PRF in English
Sean Woo's Finance, GIS and real estate English glossary. Английский глоссарий по ГИС(Географическая информационная система) и недвижимости Sean Woo's Finance. 2012