Q1: Why is a pilot survey important?
Ans: A pilot survey is crucial because it checks the clarity and relevance of questions, evaluates enumerator performance, tests the survey procedures, and helps identify practical problems. It also provides an estimate of the time and cost required for the final survey and allows necessary revisions to the questionnaire and field instructions before full-scale data collection.
Q2: Explain the sample method.
Ans: The sample method involves selecting and studying a subset of units from the whole population and drawing conclusions about the entire population from this subset. It is used to save time and cost, provided the sample is chosen so that it is representative and unbiased.
Q3: What are the qualities of a good questionnaire?
Ans: A good questionnaire should have a limited number of clear and relevant questions, use simple and non-controversial language, follow a logical order with related questions grouped together, and end with a polite request for return. It should also be tested in a pilot survey to remove ambiguity.
Q4: Mention two demerits of indirect oral investigation.
Ans: Indirect oral investigations are often less accurate and may be biased because information is second-hand. Such enquiries can lead to doubtful conclusions when respondents relay hearsay rather than direct facts.
Q5: The progress report of a railway published by the railway department is what kind of data?
Ans: The progress report published by the railway department is secondary data, since it has been collected and compiled by another agency for administrative or public use rather than gathered firsthand for a new study.
Q6: Define the census method.
Ans: The census method involves collecting data about every unit in the population relevant to the investigation. It is an exhaustive method used when complete coverage is required, though it is usually time-consuming and costly.
Q7: What do you mean by random sampling?
Ans: Random sampling means selecting units so that each unit in the universe has an equal chance of being chosen. This helps produce an unbiased sample and allows the use of probability theory for inference about the population.
Q8: Mention two sources of secondary data.
Ans: Two sources of secondary data are government publications (for example, official reports and statistical yearbooks) and semi-government publications (for example, reports of public corporations or regulatory bodies).
Q9: What is the universe in statistics?
Ans: In statistics, the universe (also called the population) is the complete set of items or individuals under study from which a sample may be drawn. It may be finite or conceptually infinite depending on the problem.
Q10: Define stratified and mixed sampling?
Ans: Stratified sampling divides the universe into homogeneous groups or strata (for example by age, income, or region) and then selects samples from each stratum to ensure representation. Mixed sampling (or multistage/mixed methods) combines two or more sampling techniques (for example, stratified followed by random sampling within strata) to suit practical requirements and improve precision.
Q11: Explain systematic sampling.
Ans: Systematic sampling arranges the population in some order (numerical, alphabetical or geographical) and then selects every nth unit to form the sample, after choosing a random starting point. It is simple to implement but care must be taken to avoid periodic patterns that could bias results.
Q12: What is convenience sampling?
Ans: Convenience sampling selects respondents who are easiest to reach or contact. It is quick and inexpensive but prone to bias, so its results are not reliably generalisable to the whole population.
Q13: Define sample.
Ans: A sample is a subset of units taken from the population that is intended to represent the population's characteristics so that conclusions about the whole population may be drawn from the study of the sample.
Q14: What are the two sources of data?
Ans: The two sources of data are primary sources, where information is collected firsthand by the investigator, and secondary sources, where information is obtained from data already collected by others.
Q15: When is a direct personal investigation suitable for primary data collection?
Ans: Direct personal investigation is suitable when the study is specific and limited in scope, when authentic and accurate information is required, when confidentiality or sensitive data necessitates direct contact, or when answers need probing and clarification through face-to-face interaction.
Q16: What is purposive or deliberate sampling?
Ans: Purposive sampling involves selecting units according to the investigator's judgement about which units are most useful or representative. It is appropriate when only certain types of respondents with specific characteristics are relevant to the study.
Q17: In what parameters is the statistical information published in the census of India?
Ans: Statistical information in the Census of India is published on parameters such as population projection, sex composition, population density, size, growth rate and distribution of the population.
Q18: Define primary data.
Ans: Primary data is information collected directly by the investigator for the first time from original sources. Common methods include surveys, interviews, observation and experiments, and such data are gathered specifically to meet the objectives of the current study.
Q19: What is quota sampling?
Ans: Quota sampling divides the universe into sections based on certain characteristics and then selects a specified number of units from each section to meet predetermined quotas. It ensures representation of key groups but is non-random and can introduce selection bias.
Q20: Define secondary data.
Ans: Secondary data are data that have already been collected by someone else and are available in published or unpublished form. They save time and cost but may be less suitable if they do not exactly match the requirements of the new study or if they are outdated.
