Principles and Techniques of Veterinary and AH Extension

SAMPLING

• If the characteristics of all members of a population were exactly the same, there would be no need of sampling procedure. But in case of social studies it is not possible to have similar characteristics of all members of population.
• The diversity of our social environment requires careful selection of sample units.

Sample

•  A well represented part of the population is known as sample.

Census

• Complete enumeration or coverage of the population is known as census.

Sampling

• It is a method of selecting a fraction of the population in such a way that it represents the whole population.

Why sampling?

• Many times it is impossible to study whole population as it is too costly and time consuming.
• Sample study provides much quicker results than does a census.
• Census study is complex and labour consuming.
• In some cases sample study provides more accurate results than census.
• Quality of study is often better with sampling than complete study.
• If the population is infinite, sampling is the only procedure to be adopted.
• It is therefore, convenient to pick up the sample and study its characteristics in detail.

Essentials of ideal sample

• Representativeness
• Independence
• Adequacy
• Homogeneity