The general category of inquiry forms include data gathering instruments through which respondents answer the question or respond to statement in writing. A questionnaire is used when factual information is gathered or desired. It is respectable research tool. It is considered as most appropriate and useful data gathering device in research project if it is properly constructed, structured and administered.
Goode and Hatt have defined questionnaire as “The word questionnaire refers to a device for securing answers to questions by using a form which the respondent fills in himself.”
A questionnaire is widely used for gathering information concerning an individual. A questionnaire is an inventory that is intended to gather information regarding specific aspect.
According to Bar, Devis and Johnson “Questionnaire is systematic compilation of questions that are submitted to sampling of population from which information is desired
Categories of questionnaire
    ·        Structured
Structured questions take a lot of time to set up but then a short time to process and analyze. The
larger the size of the sample, the more structured, closed and numerical the questionnaire may have to be.
    ·        Semi structured
The smaller the size of the sample, the less structured, more open and word-based the questionnaire may be.
   ·        Unstructured
Open questions take a shorter time to set up but a longer time to process and analyze.