What is Sampling

Sampling and Sample

Sampling is the process of drawing sample of a desired size from the population. A sample is a specimen that is representative of the population from which it has been selected. A sample can be taken from a population for various end-uses: in statistics sample of data is taken to draw conclusion about the whole data set; in research sample is taken to draw conclusions about the population parameters; in medical science a sample of the drugs is tested to know its efficiency and side effects.

Sampling has benefits

Sampling saves cost
Sampling saves cost | Source
Sampling increases scope
Sampling increases scope | Source
Sampling saves time
Sampling saves time | Source

Why Sample

Sample is taken for a variety of reasons, some benefits of sampling are as follows:

  1. A sample can help you save time as well as human and financial resources. Cost effective methods have to be used in research, medicine, statistics and other areas of study. Time is also limited and one has to draw the conclusions. Studying the whole population can be a lengthy process and often impractical too. The processing and analysis of the data in statistics can be made easier with sampling, on the other hand, the results of the research will take years and years to come out.
  2. Sampling makes the process of research and statistical studies flexible. Without sampling you cannot setup high aims in research.
  3. A sample also helps in getting the results faster, in many studies the results should be reached to the audience so that they can get benefits from the findings. For example in medical science the results of the experiments can help the humanity in many ways, taking too long time may offset the importance and the scope of that research.
  4. Sampling sometimes becomes more accurate and effective than the population because of the ease of processing data. The researcher cannot handle the data of entire population and accuracy becomes questionable.

Types of Sampling

Random sampling
Non-random sampling
Mixed sampling
Simple random sampling
Quota
Systematic sampling
Stratified random sampling
Accidental
 
Cluster sampling
Judgemental
 
 
Snowball
 
The types of sampling mentioned here are mostly used in research and statistics. There can be many other types of sampling that are used in other areas of study.

Aims in Selecting a Sample

While good sample is a useful mean to accomplish a research, badly selected sample can ruin the entire research. The data has to be selected form the sample that you have drawn. Accuracy in sample selection is therefore crucial for the validity and reliability of your research.

In selecting a sample you should try to:

  1. The sample represents the population and it should have to be highly representative of the population.
  2. Consciously or unconsciously biases should never be introduced in the sample. The sample should cover the whole population and for this purpose the accurate sampling technique should be used.
  3. It should also be ensured that every unit in the population has an equal chance of being selected.

Dis-advantages of Sampling

Sampling is a trade-off between gains and loses. There are certain dis-advantages of sampling, regardless of these drawbacks sampling is still used in several fields.

  1. Sampling may not be representative of the population because sample is only a part of the population and not the population itself.
  2. Sampling increases the chances of bias in research due to more manipulation.
  3. In non-random sampling the degree of generalizability is highly questionable.
  4. Sample should have to be big enough to represent the population. Very small sample in proportion to the population cannot be representative of the population.

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Quick Summary

  • A sample is a specimen of the population
  • It is used to study population parameters
  • Sampling saves human and non-human resources
  • Sample should have to be highly representative of the population
  • biases should be avoided in sampling
  • There are three types of sampling: random, non-random and mixed

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2 comments

Lady Guinevere profile image

Lady Guinevere 2 years ago from West Virginia

Very well put together and researched. Voted up and useful and interesting.


gulnazahmad profile image

gulnazahmad 2 years ago from Pakistan Author

Thanks a lot Guinevere :-)

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