The difference between the actual value of a parameter of the population and its estimate is the ____________.

____________ should be completed before the final survey commences.

The most common type of instrument used in survey is _____________.

______________ is known as method of complete enumeration.

____________ helps in pretesting of the questionnaire.

____________ questions are easy to use and to codify for analysis.

____________ method does not allow influencing of the respondents by the interviewer.

The data in a survey are collected by _____________.

____________ is a smaller group selected from the population from which the relevant information would be sought.

______________ are mainly selected on the basis of judgement,purpose,convenience or quota.