Polling is an "attempt to measure public opinion by taking a survey of the views of a representative sample of the electorate; the science of opinion sampling is called psephology. Most standard polls take random samples of around a thousand voters, which give results that should be accurate to within three percentage points, 95% of the time."
From Opinion Poll. (2018). In Helicon (Ed.), The Hutchinson unabridged encyclopedia with atlas and weather guide. Abington, UK: Helicon. Retrieved from https://search-credoreference-com.castleton.idm.oclc.org/content/title/heliconhe