Definition: The Sampling is a statistical method wherein a certain group of representative items is selected from the universe, called as a sample, on the basis of which the conclusion for the entire population is drawn.
In sampling, the data are collected from few representative items of the universe that best describes the characteristics of the population. This method is used to overcome the limitation of the census method which is both costly and time-consuming. Thus, the purpose of the sampling is to draw inference about the population by studying a small part of it, which is more convenient and less costly.
There are two important Principles on which the sampling theory depends upon:
- Principle of ‘Statastical Regularity.’
- Principle of ‘Inertia of Large Numbers.’
One of the major advantages of the sampling method is, it is economical and less time-consuming. Also, it is simple to understand and can be applied successfully in the case of the larger universe under study.
But however, it is only the partial investigation of the universe the result obtained could be biased or partially correct. This method cannot be applied successfully in the situation where the universe is small and also selecting the representative sample is quite difficult.