Important Questions and Answers for Class 11 Economics Chapter 2 Collection of Data 2025-26

1. Multiple choice questions.

Q1. Which of the following best describes primary data?

• (a) Data collected by someone else for another purpose
• (b) Data gathered first-hand by the investigator
• (c) Data published in books and newspapers
• (d) Data from government statistical reports

Answer: (b) Data gathered first-hand by the investigator. Primary data is collected directly from the source through the researcher's own efforts.

Q2. Which of the following is an advantage of the mailed questionnaire method?

• (a) Maintains anonymity of respondents
• (b) Allows explanation of questions on the spot
• (c) Provides highest response rate
• (d) Suitable for illiterate respondents

Answer: (a) Maintains anonymity of respondents. The mailed questionnaire method does not involve direct contact, protecting respondents' identity.

Q3. The “lottery method” is associated with which type of sampling?

• (a) Non-random sampling
• (b) Quota sampling
• (c) Random sampling
• (d) Judgement sampling

Answer: (c) Random sampling. The lottery method ensures each member has an equal chance, fulfilling the main feature of random sampling.

Q4. A census involves:

• (a) Collection of data from a sample only
• (b) Collection of data from government records only
• (c) Collection of data from all units of the population
• (d) Observing only one unit in detail

Answer: (c) Collection of data from all units of the population. Census covers each person/item in the defined group.

Q5. Which is NOT a non-sampling error?

• (a) Errors in data acquisition
• (b) Sampling bias
• (c) Non-response error
• (d) Difference between sample mean and population mean due to chance

Answer: (d) Difference between sample mean and population mean due to chance. This is a sampling error, not a non-sampling error.

2. Very Short Answer (VSA).

Q6. What is secondary data?

Answer: Secondary data refers to data that has been collected and processed by someone else, often found in books, reports, and official records.

Q7. Define population in statistics.

Answer: Population is the total group of individuals or items under study, from which samples may be drawn for analysis.

Q8. What is a pilot survey?

Answer: A pilot survey is a small-scale preliminary study conducted to test and improve the main survey questionnaire and process.

Q9. Give one feature of open-ended questions.

Answer: Open-ended questions allow respondents to answer in their own words, providing detailed and individualized responses.

Q10. State the main aim of data collection in economics.

Answer: The main aim is to collect relevant facts to understand, explain, and analyze economic problems or situations.

3. Short Answer Questions.

Q11. Explain the difference between personal interview and telephone interview as methods of data collection.

Answer: In a personal interview, the investigator meets the respondent face-to-face, enabling explanation and observation. It is time-consuming and costly. In a telephone interview, questions are asked by phone, allowing quick access and saving costs, but physical reactions cannot be observed and some people may be unreachable.

Q12. What is sampling bias? How does it affect the results of a survey?

Answer: Sampling bias occurs when certain members of the population are systematically excluded from the sample. This leads to non-representative results and affects the reliability and validity of the findings, as the sample does not reflect the whole population.

Q13. State two points to remember while framing a questionnaire for data collection.

Answer: (i) The questionnaire should be short with easy-to-understand, unambiguous questions. (ii) Questions must be arranged from general to specific to keep respondents comfortable, avoiding double negatives and leading questions.

Q14. Distinguish between census and sample survey.

Answer: A census collects data from every member of the population, giving complete information but requiring time and resources. A sample survey gathers data from a representative subset, saving resources but may involve sampling errors.

4. Long Answer Questions.

Q15. Discuss the various modes of data collection, along with their advantages and disadvantages.

Answer: The main modes are (i) personal interview, (ii) mailed questionnaire, and (iii) telephone interview. Personal interviews allow all types of questions and clarification but are expensive and time-consuming. Mailed questionnaires are cost-effective and suitable for remote respondents, though response rates might be lower and no clarification is possible. Telephone interviews are quick and have moderate costs, but cannot observe reactions and may limit complex questions.

1. Personal interviews: detailed, costly.
2. Mailed questionnaires: cheap, less interactive.
3. Telephone interviews: quick, not suitable for all questions.

Q16. Explain the importance and limitations of using secondary data in statistical studies.

Answer: Secondary data saves time and resources, as the data is already collected and processed by agencies like government, CSO, or NSSO. However, it may not match the specific purpose of the current research and can lack reliability. The researcher must assess its suitability, accuracy, and timeliness before use.

1. Advantages: quick, cost-effective access to large data sets.
2. Limitations: may not suit present objectives, possible outdated or inappropriate classification.

Q17. “Non-sampling errors are often more serious than sampling errors.” Discuss with examples.

Answer: Non-sampling errors arise due to faulty data collection, recording, non-response, or sampling bias. They can occur even in censuses and large samples, affecting data quality significantly. For instance, misunderstanding questions or recording wrong responses can distort results more than chance differences in sampling, making non-sampling errors more severe and harder to control.

5. Assertion–Reason type questions.

Assertion (A): Census method provides more reliable data than sample survey.
Reason (R): Census collects information from every unit of population.

• (a) A and R are true, and R is the correct explanation of A
• (b) A and R are true, but R is not the correct explanation of A
• (c) A is true, but R is false
• (d) A is false, but R is true

Answer: (a) A and R are true, and R is the correct explanation of A. Census covers all units, ensuring data’s reliability.

Assertion (A): Random sampling is useful for eliminating bias.
Reason (R): In random sampling, every item has an equal chance of selection.

• (a) A and R are true, and R is the correct explanation of A
• (b) A and R are true, but R is not the correct explanation of A
• (c) A is true, but R is false
• (d) A is false, but R is true

Answer: (a) A and R are true, and R is the correct explanation of A. Equal selection chances reduce sampling bias.

6. Case-based questions.

A team of researchers plans to study the dietary habits of students in a city. They use a questionnaire with both multiple-choice and open-ended questions, and select 100 students at random out of a population of 1000. Some students do not respond, and a few responses are incomplete.

(i) What type of sampling method is being used?

Answer: Random sampling, as students are chosen randomly from the population.

(ii) Name two types of questions included in the questionnaire.

Answer: Multiple-choice (closed-ended) and open-ended questions.

(iii) Which non-sampling error is likely to occur here?

Answer: Non-response error, as not all selected students replied or gave complete answers.

(iv) What is the sample size in this study?

Answer: The sample size is 100 students.

7. Match the following.

Questions	Answer
1. Census	(B) Complete enumeration
2. Pilot Survey	(D) Preliminary study to test questionnaire
3. Random Sampling	(A) Lottery method
4. Non-response Error	(C) Selected people do not respond

8. Numericals / Derivations.

Q18. In a class of 10 students, how many possible samples of 3 students can be made?

Answer: There are 120 possible samples.

1. Given: Total students = 10, Sample size = 3
2. Formula: Number of combinations = $^{10}C_3 = \dfrac{10!}{3!7!}$
3. Calculation: $= \dfrac{10 \times 9 \times 8}{3 \times 2 \times 1} = 120$
4. Final answer: 120 samples

Why learning about data collection is crucial for Class 11 Economics?

Understanding Statistics for Economics Class 11 Chapter 2 questions and answers builds a solid base for analyzing factual data. With well-structured practice, you can easily approach Collection of Data Class 11 extra questions and answers and interpret survey findings, making economics simple and approachable.

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