Sampling Techniques

Basics of Sampling Techniques

  • Sampling is an essential part of experimental design, which involves the selection of individual observations.
  • It’s impossible to study entire populations in detail, so representative samples are collected.
  • Random sampling ensures every member of a population has an equal chance of being selected.
  • Stratified sampling divides the population into groups, or strata, then selects samples from each group.

Importance of Sample Size and Range

  • Choose a sample size that is large enough to be representative, but manageable for your study.
  • Range involves the area in which your sampling takes place, it should encapsulate the majority of variances within your study.

Common Sampling Techniques in Biology

  • Quadrat sampling: This uses a square frame to isolate a specific area for study - useful in plant or stationary animal studies.
  • Pitfall traps: These are used to sample small invertebrates. It’s a trap that is level with the ground, which an animal can fall into.
  • Transect sampling: A line transect is a line along which observations are made, useful for studying changes in habitats.

Factors to Consider

  • Use of appropriate sampling technique will ensure the reliability and accuracy of your data.
  • Always remain aware of sampling bias, which can skew your results.

Errors and Improvements in Sampling

  • Always account for random error and systematic error which can affect your results. Random errors occur due to chance, systematic errors occur due to mistakes in experimental procedure.
  • Repeat sampling and use of controls can help to minimize errors and improve your sampling technique.