Advertisement

Epidemiology pp 97-109 | Cite as

The Origin of Information: Sampling

  • Klaus Krickeberg
  • Pham Van Trong
  • Pham Thi My Hanh
Chapter
Part of the Statistics for Biology and Health book series (SBH)

Abstract

Sampling from medical records is a classical technique in medical and epidemiologic research. Let us look at a fictitious example from the pre-computer age. Suppose Dr. Q. wants to find the frequency of a risk factor A among all patients who were treated in a given ward of his hospital during the period 1950–1959. There had been N = 9850 such patients, and for every one of them a medical record in the form of a file exists where the presence or absence of A is recorded. Dr. Q. could look through the whole (dust covered) set of files and count the occurrence of A in it. Suppose that he finds it 271 times; this would be the “frequency” he is looking for. The so-called “relative frequency”, or “proportion”, of A is more instructive; it is equal to

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Klaus Krickeberg
    • 1
  • Pham Van Trong
    • 2
  • Pham Thi My Hanh
    • 2
  1. 1.Grosser Kamp 4BielefeldGermany
  2. 2.Faculty of Public HealthThai Binh Medical UniversityThai BinhVietnam

Personalised recommendations