Sampling Technique

The population or universe consists of a number of units usually very large and sometimes infinitely many. In most of the cases, it is practically not possible to include all units of the population for a study. For the studying purpose a part of the population are taken or considered. On the basis of this part the inference of the whole population is made. This technique of taking a part of the population for a studying purpose is known as sampling technique.

Sampling is a part of our day-to-day life which we use advertently or inadvertently. For instance, a housewife takes one or two grains of rice from the cooking pan and decide whether the rice is cooked or not. A consumer takes few grains of pulses and decides to buy it or not. The intelligence of the individuals in a subject is estimated by the university by giving them a four hour test at post graduate level. In all these situations, sampling is invertible and given satisfactory results.

Even in those cases where complete enumeration is possible, it is preferred to use sampling technique due to the facts that complete enumeration is much more time consuming and expensive, requires more skilled and technical personal, more errors etc.

Sampling is a tool which enables us to draw conclusions about the characteristics of the population after studying only those objects or items that are included in the sample. Sampling technique has a great importance in every field of life. It is widely used as a mean of collecting information to meet a definite need in government, industries and trade, physical and life sciences and technology, social, educational and economical problem. All walks of life are covered by sampling techniques. It is impossible to give the full range of importance of it. However, some specified importance of sampling techniques are given as follows:

• When the scope of the investigation is very wide and the population is not completely known, then sampling technique is only the way of investigation.
• Sampling can saves time, money and other resources. When time, money and other resources are limited for the studying purpose then it is only the means of overcome such remedies.
• It gives more accurate results when results with maximum accuracy or reliability with a fixed budget, or with a minimum number of units with specified degree of reliability are required, then the sampling technique is used.
• When the population is infinite e.g. the population of stars in the sky, the water in the ocean etc. and the items or units is destroyed under investigation e.g. the population of light bulbs etc., then sampling is inevitable.
• The results obtained through the complete enumeration can be cross checked by using sampling technique.