Non probability sampling advantages and disadvantages pdf
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- Non-Probability Sampling: Definition, types, Examples, and advantages
- Type of Sampling
- Non Probability Sampling | Methods | Advantages & Disadvantages
- Nonprobability Sampling
Non-Probability Sampling: Definition, types, Examples, and advantages
We use Sampling techniques to reduce the time, money and other resources to be invested for our survey. Probability Sampling techniques are widely used in surveys for fair and unbiased sampling process. In some cases, the randomness of Probability Sampling can not address the niche need of the surveyors. In this case, we use Non- Probability Sampling. Every time a media person takes an interview of a person on the street or a researcher asks subject experts for opinions to get an idea of what the general populace thinks about an issue, the surveyor is saving time and resource by using their judgement to select samples. While the analysis is not statistically accurate, it is helpful to get an idea of the subject under study. This way of applying judgment in a sampling process reduces the opportunity that all the items in the population have equal chances of being selected and is rightly called non-probability sampling.
Home QuestionPro Products Audience. Definition: Non-probability sampling is defined as a sampling technique in which the researcher selects samples based on the subjective judgment of the researcher rather than random selection. It is a less stringent method. This sampling method depends heavily on the expertise of the researchers. It is carried out by observation, and researchers use it widely for qualitative research.
Type of Sampling
Non-probability sampling represents a group of sampling techniques that help researchers to select units from a population that they are interested in studying. Collectively, these units form the sample that the researcher studies [see our article, Sampling: The basics , to learn more about terms such as unit , sample and population ]. A core characteristic of non-probability sampling techniques is that samples are selected based on the subjective judgement of the researcher, rather than random selection i. Whilst some researchers may view non-probabilit y sampling techniques as inferior to probability sampling techniques, there are strong theoretical and practical reasons for their use. This article discusses the principles of non-probability sampling and briefly sets out the types of non-probability sampling technique discussed in detail in other articles within this site.
It would normally be impractical to study a whole population, for example when doing a questionnaire survey. Sampling is a method that allows researchers to infer information about a population based on results from a subset of the population, without having to investigate every individual. Reducing the number of individuals in a study reduces the cost and workload, and may make it easier to obtain high quality information, but this has to be balanced against having a large enough sample size with enough power to detect a true association. Calculation of sample size is addressed in section 1B statistics of the Part A syllabus. If a sample is to be used, by whatever method it is chosen, it is important that the individuals selected are representative of the whole population.
Non Probability Sampling | Methods | Advantages & Disadvantages
The difference between nonprobability and probability sampling is that nonprobability sampling does not involve random selection and probability sampling does. Not necessarily. But it does mean that nonprobability samples cannot depend upon the rationale of probability theory.
When to use it. Ensures a high degree of representativeness, and no need to use a table of random numbers. When the population is heterogeneous and contains several different groups, some of which are related to the topic of the study. Ensures a high degree of representativeness of all the strata or layers in the population. Possibly, members of units are different from one another, decreasing the techniques effectiveness.
Convenience sampling also known as grab sampling , accidental sampling , or opportunity sampling is a type of non-probability sampling that involves the sample being drawn from that part of the population that is close to hand. This type of sampling is most useful for pilot testing. A convenience sample is a type of non-probability sampling method where the sample is taken from a group of people easy to contact or to reach. For example, standing at a mall or a grocery store and asking people to answer questions would be an example of a convenience sample. This type of sampling is also known as grab sampling or availability sampling. There are no other criteria to the sampling method except that people be available and willing to participate.
Non-probability sampling derives its control from the judgement of the investigator. In non-probability sampling, the cases are selected on bases of availability and interviewer judgement. Non-probability sampling has its strength in the area of convenience. Convenience sampling is generally known as careless, unsystematic, accidental or opportunistic sampling. The sample is selected according to the convenience of the sample. The researcher selects certain units convenient to him. It requires no pre-planning for the selection of items.