extrapolation vs surmise

extrapolation

noun
  • An inference about some hypothetical situation based on known facts. 

  • A calculation of an estimate of the value of some function outside the range of known values. 

  • The diametric opposite of interpolation. 

surmise

noun
  • Thought, imagination, or conjecture, which may be based upon feeble or scanty evidence; suspicion; guess. 

  • Reflection; thought; posit. 

verb
  • To imagine or suspect; to conjecture; to posit with contestable premises. 

How often have the words extrapolation and surmise occurred in a corpus of books? (source: Google Ngram Viewer )