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.