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Sampling (statistics)

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❶Once selected, I would have to go to the shelf, locate the book, and record when it last circulated.

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How a Simple Random Sample Is Generated

It is also considered as a fair way of selecting a sample from a given population since every member is given equal opportunities of being selected. Another key feature of simple random sampling is its representativeness of the population. Theoretically, the only thing that can compromise its representativeness is luck.

If the sample is not representative of the population, the random variation is called sampling error. An unbiased random selection and a representative sample is important in drawing conclusions from the results of a study.

Remember that one of the goals of research is to be able to make conclusions pertaining to the population from the results obtained from a sample. Due to the representativeness of a sample obtained by simple random sampling, it is reasonable to make generalizations from the results of the sample back to the population.

One of the most obvious limitations of simple random sampling method is its need of a complete list of all the members of the population. Please keep in mind that the list of the population must be complete and up-to-date. This list is usually not available for large populations.

In cases as such, it is wiser to use other sampling techniques. Check out our quiz-page with tests about:. Retrieved Sep 12, from Explorable. The text in this article is licensed under the Creative Commons-License Attribution 4. You can use it freely with some kind of link , and we're also okay with people reprinting in publications like books, blogs, newsletters, course-material, papers, wikipedia and presentations with clear attribution.

Don't have time for it all now? No problem, save it as a course and come back to it later. Share this page on your website: This article is a part of the guide: Select from one of the other courses available: Don't miss these related articles:. There are no strict rules to follow, and the researcher must rely on logic and judgment.

The population is defined in keeping with the objectives of the study. Sometimes, the entire population will be sufficiently small, and the researcher can include the entire population in the study. This type of research is called a census study because data is gathered on every member of the population. Usually, the population is too large for the researcher to attempt to survey all of its members. A small, but carefully chosen sample can be used to represent the population. The sample reflects the characteristics of the population from which it is drawn.

Sampling methods are classified as either probability or nonprobability. In probability samples, each member of the population has a known non-zero probability of being selected. Probability methods include random sampling, systematic sampling, and stratified sampling. In nonprobability sampling, members are selected from the population in some nonrandom manner.

These include convenience sampling, judgment sampling, quota sampling, and snowball sampling. The advantage of probability sampling is that sampling error can be calculated.

Sampling error is the degree to which a sample might differ from the population. When inferring to the population, results are reported plus or minus the sampling error.

In nonprobability sampling, the degree to which the sample differs from the population remains unknown. Random sampling is the purest form of probability sampling. Each member of the population has an equal and known chance of being selected.

When there are very large populations, it is often difficult or impossible to identify every member of the population, so the pool of available subjects becomes biased. Systematic sampling is often used instead of random sampling. It is also called an Nth name selection technique. After the required sample size has been calculated, every Nth record is selected from a list of population members.

As long as the list does not contain any hidden order, this sampling method is as good as the random sampling method. Its only advantage over the random sampling technique is simplicity.

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Simple random sampling (also referred to as random sampling) is the purest and the most straightforward probability sampling strategy. It is also the most popular method for choosing a sample among population for a wide range of purposes.

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Disadvantages of Simple Random Sampling One of the most obvious limitations of simple random sampling method is its need of a complete list of all the members of the population. Please keep in mind that the list of the population must be .

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In probability sampling it is possible to both determine which sampling units belong to which sample and the probability that each sample will be selected. The following sampling methods are examples of probability sampling: Of the five methods listed above, students have the most trouble. Random sampling refers to a variety of selection techniques in which sample members are selected by chance, but with a known probability of selection. Most social science, business, and agricultural surveys rely on random sampling techniques for the selection of survey participants or sample units, where the sample units may be persons.

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Cluster random sampling – divides the population into clusters, clusters are randomly selected and all members of the cluster selected are sampled A practical how to, offers an overview of sampling methods for quantitative research and contrasts them with qualitative method for further understanding. Sampling Methods in Qualitative and. Simple random sampling is the most basic and common type of sampling method used in quantitative social science research and in scientific research generally. The main benefit of the simple random sample is that each member of the population has an equal chance of being chosen for the study.