Näidisvalim

Näidisvalim is an Estonian term used in statistics to denote a subset of individuals or items drawn from a larger population for the purpose of analysis. A näidisvalim is studied to infer properties of the whole population, especially when surveying or testing the entire population is impractical, costly, or impossible. The concept is central to research design, surveys, experiments, and quality control.

Etymology and usage: Näidisvalim combines näidis, meaning an example or specimen, with valim, meaning selection or sampling. In Estonian statistical literature and education, the term is used to refer to any sample chosen to represent a larger group, with the aim of making valid inferences about that group.

Methods and design: A näidisvalim can be drawn by probabilistic methods, such as random sampling, stratified sampling, cluster sampling, or systematic sampling, which support estimation of sampling error and enable formal inference. Non-probability methods, including purposive or convenience sampling, may be used when probability sampling is not feasible, but they typically limit the generalizability of results and require careful interpretation.

Quality and bias: The representativeness of a näidisvalim is crucial. Bias can arise from selection procedures, nonresponse, or measurement errors. Good practice includes careful sampling design, documentation of methods, and, when appropriate, weighting or adjustment to improve representativeness.

Analysis and reporting: Analysts use standard statistical techniques to estimate population parameters from the näidisvalim, often reporting margins of error or confidence intervals and noting the sampling design and potential biases that affect interpretation.

See also: Statistical sampling, Survey sampling, Estonian statistics.