Sampling: Sampling is an old age practice in everyday life. Whenever we want to buy a huge quantity of a commodity, we decide about the total lot by simply examining a small fraction of it. It has been established that the sample survey, if planned properly, can give precise information. Since, in a survey, a part of the population is only surveyed and inference is drawn about the whole population, the results are likely to be different from the population values. But the advantage with the sample survey is that this type of error can be measured and controlled. Similarly, the errors which arise due to human factors at the stage of ascertainment and processing of data can be eliminated considerably by employing properly trained persons in surveys. The other advantages of sample surveys are that it is less time consuming, involves less cost, has greater scope in special coverage and also, has greater operational facilities as compared to complete enumeration. It is for these reasons that sample surveys are being preferred by the government, scientific organizations, industries, institutes and others in all parts of the world.
