Preliminary Concept on Sampling

In day to day life, we come across persons making an assessment of the population through samples. A housewife tests a small quantity of rice to see if it is well cooked. An auditor checks a sample of accounts to know the number of errors in the entire population of his accounts. The importance of the theory of sampling lies in the fact that for a large population, it is neither practical nor possible to collect data for each and every number of the population. In testing the quality of the bulbs produced, by a company it is impossible to test every bulb manufactured by the company; however, it is quite sufficient if a sample is taken for testing and based on this test it is possible to draw conclusion about the population.