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  2. Area sampling frame - Wikipedia

    en.wikipedia.org/wiki/Area_sampling_frame

    A sampling frame is often defined as a list of elements of the population we want to explore through a sample survey. A slightly more general concept considers that a sampling frame is a tool that allows the identification and access to the elements of the population, even if an explicit list does not exist. [1] Traditional sampling frames are ...

  3. Sampling frame - Wikipedia

    en.wikipedia.org/wiki/Sampling_frame

    A slightly more general concept of sampling frame includes area sampling frames, whose elements have a geographic nature. Area sampling frames can be useful for example in agricultural statistics when a suitable and updated agricultural census is not available. In environmental surveys, area sampling frames may be the only option.

  4. Sample size determination - Wikipedia

    en.wikipedia.org/wiki/Sample_size_determination

    The sample size is an important feature of any empirical study in which the goal is to make inferences about a population from a sample. In practice, the sample size used in a study is usually determined based on the cost, time, or convenience of collecting the data, and the need for it to offer sufficient statistical power. In complex studies ...

  5. Systematic sampling - Wikipedia

    en.wikipedia.org/wiki/Systematic_sampling

    This is random sampling with a system. From the sampling frame, a starting point is chosen at random, and choices thereafter are at regular intervals. For example, suppose you want to sample 8 houses from a street of 120 houses. 120/8=15, so every 15th house is chosen after a random starting point between 1 and 15.

  6. Simple random sample - Wikipedia

    en.wikipedia.org/wiki/Simple_random_sample

    The concept can be extended when the population is a geographic area. [4] In this case, area sampling frames are relevant. Conceptually, simple random sampling is the simplest of the probability sampling techniques. It requires a complete sampling frame, which may not be available or feasible to construct for large populations. Even if a ...

  7. Coverage error - Wikipedia

    en.wikipedia.org/wiki/Coverage_error

    Her sampling frame might be a list of third-graders in the school district (sampling frame). Over time, it is likely that the researcher will lose track of some of the children used in the original study, so that her sample frame of adults no longer matches the sample frame of children used in the study.

  8. Quadrat - Wikipedia

    en.wikipedia.org/wiki/Quadrat

    [1] [2] A quadrat is suitable for sampling or observing plants, slow-moving animals, and some aquatic organisms. A photo-quadrat is a photographic record of the area framed by a quadrat. It may use a physical frame to indicate the area, or may rely on fixed camera distance and lens field of view to automatically cover the specified area of ...

  9. Laboratory specimen - Wikipedia

    en.wikipedia.org/wiki/Laboratory_specimen

    A laboratory specimen is sometimes a biological specimen of a medical patient's tissue, fluids, or other samples used for laboratory analysis to assist in differential diagnosis or staging of a disease process. These specimens are often the most reliable method of diagnosis, depending on the ailment.