opinion poll vs sampling

opinion poll

noun
  • A poll organized in an attempt to quantify public opinion on a subject. 

sampling

noun
  • The analysis of a group by determining the characteristics of a significant percentage of its members chosen at random. 

  • The process or technique of obtaining a representative sample. 

  • Electronically splicing pieces of previously recorded sound as part of a composition, especially as part of hip-hop or electronic dance music. 

  • A sample. 

  • The measurement, at regular intervals, of the amplitude of a varying waveform in order to convert it to digital form. 

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