4.  Define Pilot survey

Pre-testing of the questionnaire with a small group is called Pilot survey.

5.  What is census or complete enumeration?

A survey which includes every element of the population is called census method or the method of complete enumeration.

Example: The census of India which is carried out every ten years is an example for method of complete enumeration.  It is a house- to –house enquiry covering all households in India relating to demographic data on birth, death rates, life expectancy, size and composition of population etc, collected and published by the Registrar General of India.

6.  What is sample survey?

When a survey is conducted from samples or group or section of the population from which information is to be obtained it called sample survey.

7.  What is random sampling?

When individual units from the population (samples) are selected at random it is called random sampling.

8.  What is non-random sampling?

When samples are selected on the basis of the judgment, purpose, convenience or quota of the investigator, it is called non-random sampling.