Class 11th Statistics Census and Sample Methods of Collection of Data Notes

By / September 7, 2025

1. Census and Sample Inquiry

  • Census Inquiry: A method in which data is collected from each and every unit of the population.
  • Sample Inquiry: A method in which data is collected from a representative part (sample) of the population.

2. Census Method (Method of Complete Enumeration)

(a) Meaning

In the census method, information is collected from every unit of the population without leaving anyone.

(b) Suitability (5 points, one line each)

  1. Suitable when population is small.
  2. Used when high accuracy is required.
  3. Applied in government population census.
  4. Best for heterogeneous population.
  5. Suitable when sufficient resources (time, money, staff) are available.

(c) Advantages (Merits)

  1. Provides complete information.
  2. More accurate and reliable.
  3. Useful for diverse population.
  4. Data available for different characteristics.
  5. Basis for sample surveys.

(d) Disadvantages (Demerits)

  1. Very costly.
  2. Time-consuming.
  3. Requires large manpower.
  4. Not suitable for large populations.
  5. Difficult to maintain secrecy and accuracy.

3. Sample Method

(a) Meaning

In the sample method, information is collected from a small representative group (sample) of the population, and results are generalized for the whole.

(b) Suitability (5 points)

  1. Best for large populations.
  2. When time and money are limited.
  3. When quick decisions are needed.
  4. When population is homogeneous.
  5. Suitable for scientific research.

(c) Advantages (Merits)

  1. Economical and less costly.
  2. Saves time and energy.
  3. Requires fewer investigators.
  4. Suitable for large population.
  5. Scientific and more practicable.

(d) Disadvantages (Demerits)

  1. Not suitable for heterogeneous population.
  2. Chance of sampling error.
  3. May not be accurate always.
  4. Results depend on representativeness of sample.
  5. Bias may affect the results.

4. Essentials / Qualities of a Good Sample

  1. Representativeness – Must represent the population truly.
  2. Independence – Selection of one unit should not affect others.
  3. Homogeneity – Characteristics of sample should match the population.
  4. Adequacy – Sample size should be sufficient for accuracy.

5. Methods of Sampling

(a) Random Sampling

  • Meaning: Each unit of the population has an equal chance of being selected.

Ways:

  1. Lottery Method: Names/numbers written on slips and drawn randomly.
  2. Tables of Random Numbers: Pre-prepared random number tables used for selection.

Merits:

  1. Simple to understand.
  2. Free from personal bias.
  3. Equal chance to all units.
  4. Representative in nature.
  5. Scientific and objective.

Demerits:

  1. Needs complete list of population.
  2. Costly if population is large.
  3. Sometimes unrepresentative sample may be selected.
  4. Difficult in scattered population.
  5. Requires careful planning.

(b) Non-Random Sampling

(i) Purposive or Deliberate Sampling

  • Meaning: Investigator deliberately selects units which he considers typical.

Merits:

  1. Simple and convenient.
  2. Less costly.
  3. Saves time.
  4. Useful when experts are available.
  5. Suitable for specialized studies.

Demerits:

  1. Investigator’s bias.
  2. Not truly representative.
  3. Accuracy doubtful.
  4. Less scientific.
  5. Not suitable for generalizations.

(ii) Stratified / Mixed Sampling

  • Meaning: Population divided into groups (strata) and samples taken from each group.

Merits:

  1. More representative.
  2. Greater accuracy.
  3. Useful for heterogeneous population.
  4. Comparisons possible between strata.
  5. Less chance of bias.

Demerits:

  1. Requires classification of population.
  2. More expensive than simple random sampling.
  3. Complex in nature.
  4. Errors possible in dividing strata.
  5. Requires skilled investigators.

(iii) Systematic Sampling

  • Meaning: Units selected at regular intervals from ordered population list.

Merits:

  1. Simple and easy.
  2. Saves time and money.
  3. More representative than purposive.
  4. Easy to administer.
  5. Useful in large-scale surveys.

Demerits:

  1. List of population required.
  2. Periodicity may lead to bias.
  3. Not truly random.
  4. Accuracy doubtful sometimes.
  5. Less scientific than pure random sampling.

(iv) Quota Sampling

  • Meaning: Population divided into groups and fixed quota taken from each.

Merits:

  1. Simple and convenient.
  2. Less costly.
  3. Saves time.
  4. Ensures representation of groups.
  5. Useful for opinion surveys.

Demerits:

  1. Investigator’s bias.
  2. Not random in nature.
  3. Accuracy doubtful.
  4. Not suitable for large population.
  5. Less scientific.

(v) Convenience Sampling

  • Meaning: Samples selected according to convenience of investigator.

Merits:

  1. Very easy.
  2. Saves time and money.
  3. Useful for preliminary studies.
  4. Requires less planning.
  5. Convenient when population is scattered.

Demerits:

  1. Highly biased.
  2. Not representative.
  3. Accuracy doubtful.
  4. Unscientific method.
  5. Not suitable for serious studies.

6. Reliability of Sampling Data

  • Sampling results are reliable if:
  1. Sample is representative.
  2. Sample size is adequate.
  3. Method of sampling is scientific.
  4. Trained investigators are used.
  5. Errors are minimized.

7. Difference Between Census and Sampling Method

BasisCensus MethodSampling Method
CoverageAll units of population studied.Only a part (sample) studied.
SuitabilitySmall population, high accuracy.Large population, limited resources.
AccuracyMore accurate and reliable.Depends on sample; less accurate.
CostVery costly.Cheaper.
TimeTime-consuming.Saves time.
Nature of ItemsSuitable for heterogeneous population.Suitable for homogeneous population.
VerificationVerification of characteristics possible.Verification difficult.

🧠 PREMIUM MIND MAP
Class 11 Statistics (Economics)
Collection of Data

πŸ“Š COLLECTION OF DATA
⬇

πŸ‘₯ Population

Entire group under study
Also called Universe
People / Objects / Events

πŸ› Census Method

Studies every unit
Highly Accurate
Expensive
Time-consuming
Suitable for small population

🎯 Sampling Method

Studies selected units
Economical
Quick Results
Less Expensive
Suitable for large population

βœ… Advantages

Reliable Information
Helps Decision Making
Useful in Planning
Better Analysis

⚠ Limitations

Wrong Sample β†’ Wrong Result
Census is Costly
Requires Skilled Investigators
Time Constraint

πŸ’‘ Applications

Population Census
Market Survey
Election Poll
Business Research
Government Planning
πŸ“Š Premium Diagrams – Collection of Data

Diagram 1 – Population β†’ Census Method

πŸ‘¨πŸ‘©πŸ‘§πŸ‘¦
POPULATION
(All Units)
➑
πŸ›
CENSUS METHOD
➑
Every Unit is Studied
➑
Highly Accurate Results

Diagram 2 – Population β†’ Sampling Method

πŸ‘¨πŸ‘©πŸ‘§πŸ‘¦
POPULATION
➑
🎯
Representative Sample
➑
Statistical Analysis
➑
Conclusion

Diagram 3 – Census vs Sampling

πŸ› Census Method🎯 Sampling Method
Studies every unitStudies selected units
Highly accurateReasonably accurate
Time-consumingQuick
ExpensiveEconomical
Suitable for small populationSuitable for large population

Diagram 4 – Steps in Collection of Data

1️⃣
Define Objective
⬇
2️⃣
Identify Population
⬇
3️⃣
Choose Method
⬇
πŸ› Census
OR
🎯 Sampling
⬇
4️⃣ Collect Data
⬇
5️⃣ Analyse Data
⬇
6️⃣ Draw Conclusions

Diagram 5 – Decision Tree

Need to Collect Data
⬇
Small Population
Large Population
⬇
πŸ› Use Census Method
🎯 Use Sampling Method
πŸ“Š PREMIUM INFOGRAPHICS
Collection of Data

🌍 Population vs Sample

πŸ‘¨πŸ‘©πŸ‘§πŸ‘¦πŸ‘¨πŸ‘©πŸ‘¦πŸ‘§πŸ‘¨πŸ‘©πŸ‘§πŸ‘¦

POPULATION
Entire Group
➑
🎯

Representative
Selection
➑
πŸ‘¨πŸ‘©πŸ‘§

SAMPLE
Small Part
➑
πŸ“ˆ

Statistical
Analysis

βš– Census Method vs Sampling Method

πŸ› Census Method

βœ… Studies every unit

βœ… Maximum accuracy

βœ… More expensive

βœ… Time-consuming

βœ… Suitable for small populations

🎯 Sampling Method

βœ… Studies selected units

βœ… Saves time

βœ… Economical

βœ… Quick results

βœ… Suitable for large populations

πŸ“š One-Minute Revision Chart

TopicRemember
PopulationEntire group under study
SampleRepresentative part of population
CensusEvery unit is investigated
SamplingOnly selected units are investigated
Best for Small PopulationCensus Method
Best for Large PopulationSampling Method
Fastest MethodSampling
Most Accurate MethodCensus

🎯 CBSE Exam Memory Trick

C
Complete Study
➑
Census
➑
S
Selected Units
➑
Sampling

🧠 Remember:

Census = Complete Population
Sampling = Selected Population

πŸ“˜ Class 11 Statistics for Economics
Chapter – Collection of Data
βœ… Part 3A – MCQs (1–10)

Instructions:
  • Choose the most appropriate answer.
  • Each question carries 1 mark.
  • Based on the latest CBSE Class 11 Statistics for Economics (NCERT).

Q1. Statistics begins with the process of:

A. Tabulation
B. Collection of Data
C. Interpretation
D. Classification

Q2. Collection of data refers to:

A. Arranging data in rows and columns
B. Gathering information systematically for analysis
C. Drawing diagrams and graphs
D. Calculating averages

Q3. The complete set of units under investigation is called:

A. Sample
B. Population (Universe)
C. Frequency
D. Observation

Q4. Which method studies every unit of the population?

A. Sampling Method
B. Census Method
C. Random Method
D. Interview Method

Q5. Which of the following is the best example of the Census Method?

A. Survey of 200 households in a city
B. Survey of 50 students in a school
C. Population Census of India
D. Opinion poll before elections

Q6. A representative part selected from the population is known as:

A. Frequency
B. Census
C. Sample
D. Schedule

Q7. Which method is generally preferred when the population is very large?

A. Census Method
B. Sampling Method
C. Complete Enumeration Method
D. Observation Method

Q8. Which of the following is an advantage of the Sampling Method?

A. It studies every unit.
B. It is more expensive than Census.
C. It saves both time and cost.
D. It is always 100% accurate.

Q9. Which one of the following is an advantage of the Census Method?

A. Less expensive
B. Faster results
C. Higher degree of accuracy
D. Requires fewer investigators

Q10. The main objective of collecting data is to:

A. Increase the size of the population
B. Draw meaningful conclusions after analysis
C. Decorate statistical reports
D. Prepare colourful charts only

βœ… Answer Key (MCQs 1–10)

QuestionAnswer
1B
2B
3B
4B
5C
6C
7B
8C
9C
10B

πŸ“š Quick Revision

  • βœ… Population = Entire group under study.
  • βœ… Sample = Representative part of the population.
  • βœ… Census studies every unit.
  • βœ… Sampling studies selected units only.
  • βœ… Census is more accurate but costly.
  • βœ… Sampling is quicker and economical.

πŸ“˜ Class 11 Statistics for Economics
Chapter – Collection of Data
βœ… Part 3C – MCQs (21–30)

Instructions:
  • Choose the correct answer.
  • Each question carries 1 mark.
  • Based on the latest CBSE Class 11 Statistics for Economics (NCERT).

Q21. Which method is most suitable when the population is small?

A. Sampling Method
B. Census Method
C. Random Survey
D. Pilot Survey

Q22. Which of the following is an example of a sample?

A. Every student in a school
B. Every farmer in a district
C. 100 voters selected from a city
D. Entire population of India

Q23. Which method generally requires more investigators?

A. Sampling Method
B. Census Method
C. Random Sampling
D. None of these

Q24. Sampling method is mainly used because it:

A. Eliminates all errors
B. Covers every unit
C. Saves time and money
D. Is compulsory by law

Q25. Which statement is correct?

A. Every sample is a population.
B. Every population is a sample.
C. A sample is a part of the population.
D. Population and sample are the same.

Q26. Which method is commonly used in market research?

A. Census Method
B. Sampling Method
C. Complete Enumeration
D. Population Census

Q27. The reliability of sampling mainly depends on:

A. Colour of the questionnaire
B. Size and representativeness of the sample
C. Number of graphs prepared
D. Printing quality of the report

Q28. Which of the following is NOT a characteristic of a good sample?

A. Representative
B. Free from bias
C. Selected scientifically
D. Selected only from one small group

Q29. Census Method is generally preferred when:

A. Quick results are needed
B. Population is extremely large
C. Highest possible accuracy is required
D. Funds are limited

Q30. Which of the following is the final step after collecting statistical data?

A. Ignoring the data
B. Analysing and drawing conclusions
C. Destroying the records
D. Selecting another sample

βœ… Answer Key (21–30)

QuestionAnswer
21B
22C
23B
24C
25C
26B
27B
28D
29C
30B

πŸ“˜ Class 11 Statistics for Economics
Chapter – Collection of Data
βœ… Part 3D – MCQs (31–40)

Instructions:
  • Choose the most appropriate answer.
  • Each question carries 1 mark.
  • Based on the latest CBSE Class 11 Statistics for Economics (NCERT).

Q31. Which method is preferred when complete accuracy is required?

A. Sampling Method
B. Census Method
C. Random Survey
D. Pilot Survey

Q32. Which of the following is the biggest disadvantage of the Census Method?

A. Low accuracy
B. Saves time
C. Expensive and time-consuming
D. Covers only selected units

Q33. Which of the following surveys generally uses the Sampling Method?

A. National Population Census
B. Opinion Poll before Elections
C. Counting all trees in a small park
D. Survey of every employee in a small office

Q34. A sample should represent:

A. Only rich people
B. Only urban areas
C. The entire population
D. Only one section of society

Q35. Which of the following statements is FALSE?

A. Census studies every unit.
B. Sampling studies selected units.
C. Sampling always gives 100% accurate results.
D. Census generally costs more than sampling.

Q36. Which method is more economical?

A. Census Method
B. Sampling Method
C. Complete Enumeration
D. Both are equally economical

Q37. Which factor should be considered while selecting a method of data collection?

A. Size of the population
B. Time available
C. Cost involved
D. All of the above

Q38. Which of the following is an example of a population?

A. 100 passengers selected from a train
B. All employees of a company
C. 20 houses selected from a village
D. 50 students chosen for a survey

Q39. Which of the following best describes a sample?

A. The complete population
B. A representative part of the population
C. Only government data
D. Data collected from one person

Q40. The main purpose of selecting a sample is to:

A. Increase the population size
B. Save time and cost while obtaining reliable information
C. Eliminate the need for analysis
D. Replace statistical methods

βœ… Answer Key (31–40)

QuestionAnswer
31B
32C
33B
34C
35C
36B
37D
38B
39B
40B

πŸ“˜ Class 11 Statistics for Economics
Chapter – Collection of Data
βœ… Part 3E – MCQs (41–50)

Instructions:
  • Choose the most appropriate answer.
  • Each question carries 1 mark.
  • Based on the latest CBSE Class 11 Statistics for Economics (NCERT).

Q41. Which method provides information about every unit of the population?

A. Sampling Method
B. Census Method
C. Observation Method
D. Interview Method

Q42. Which of the following is most suitable for conducting an opinion poll before an election?

A. Census Method
B. Sampling Method
C. Population Census
D. Complete Enumeration

Q43. Which of the following is an essential characteristic of a good sample?

A. Large size only
B. Representative of the population
C. Selected from one locality only
D. Includes every unit

Q44. Which method is generally more expensive?

A. Sampling Method
B. Census Method
C. Random Sampling
D. Stratified Sampling

Q45. Which of the following statements is correct?

A. Census Method studies only selected units.
B. Sampling Method always studies every unit.
C. Census Method generally provides more accurate results than Sampling Method.
D. Sampling Method is more expensive than Census Method.

Q46. Which of the following is NOT an advantage of the Sampling Method?

A. Saves time
B. Economical
C. Covers every unit of the population
D. Suitable for large populations

Q47. A researcher selects 500 households from a city of 2 lakh households for a survey. This is an example of:

A. Census Method
B. Sampling Method
C. Population Census
D. Complete Enumeration

Q48. Which factor is least important while deciding between Census and Sampling?

A. Size of the population
B. Time available
C. Cost involved
D. Favourite colour of the investigator

Q49. Which of the following statements is TRUE?

A. Population always refers only to human beings.
B. A sample is always equal to the population.
C. Population may consist of people, objects or events.
D. Sampling Method is never used in business research.

Q50. The primary purpose of collecting statistical data is to:

A. Increase the sample size
B. Make decisions based on analysed information
C. Prepare attractive tables only
D. Reduce the population

βœ… Answer Key (41–50)

QuestionAnswer
41B
42B
43B
44B
45C
46C
47B
48D
49C
50B

πŸ“š Final Revision Points

  • βœ… Population is the complete set of units under study.
  • βœ… Sample is a representative part of the population.
  • βœ… Census Method investigates every unit and provides greater accuracy.
  • βœ… Sampling Method is economical, faster and suitable for large populations.
  • βœ… The choice between Census and Sampling depends on time, cost, population size and purpose of the investigation.
  • βœ… Statistical data should always be collected systematically to draw meaningful conclusions.

πŸ“˜ Class 11 Statistics for Economics
Chapter – Collection of Data
βœ… Part 4A – Competency-Based Questions (1–10)

Instructions:
  • Read each situation carefully.
  • Apply the concepts of the chapter to answer.
  • Based on the latest CBSE competency-based pattern.

Q1. A school principal wants to know the average height of 2,000 students. She measures the height of only 200 students selected from different classes.

Question: Which method of data collection is being used? Give one reason.
Answer:
Method: Sampling Method.
Reason: Only a representative part (200 students) of the total population (2,000 students) is studied.

Q2. The Government collects information from every household during the Population Census.

Question: Identify the method used and state one advantage.
Answer:
Method: Census Method.
Advantage: It provides highly accurate and comprehensive information because every unit is covered.

Q3. A company surveys only 500 customers out of 50,000 customers to know their satisfaction level.

Question: Why is this method suitable?
Answer:
Sampling is suitable because it saves time and cost while still providing reliable results if the sample is representative.

Q4. A researcher selects respondents only from one street of a city and claims the results represent the whole city.

Question: Is the sample appropriate? Give a reason.
Answer:
No. The sample is not representative because it includes respondents from only one street, which may lead to biased conclusions.

Q5. A survey is to be completed within two days with a limited budget.

Question: Which method should be preferred?
Answer:
Sampling Method should be preferred because it is faster and more economical.

Q6. A factory owner checks every product before dispatching it.

Question: Which method does this resemble?
Answer:
It resembles the Census Method because every unit is examined.

Q7. A survey covers all farmers in a small village.

Question: Why is the selected method appropriate?
Answer:
Since the population is small, Census Method is practical and provides complete information.

Q8. A researcher wants reliable results but has limited funds.

Question: Which method should be adopted?
Answer:
Sampling Method should be adopted because it reduces cost while providing reliable results through a representative sample.

Q9. During an election survey, only young voters are interviewed.

Question: Will the findings represent all voters? Why?
Answer:
No. The sample is biased because it excludes other age groups and is not representative of the entire voting population.

Q10. A health department wants exact information about every patient affected by a rare disease in one district.

Question: Which method should be used and why?
Answer:
The Census Method should be used because complete and accurate information about every patient is required.

πŸ“˜ Class 11 Statistics for Economics
Chapter – Collection of Data
βœ… Part 4B – Competency-Based Questions (11–20)

Instructions:
  • Read each situation carefully.
  • Apply the concepts of the chapter to answer.
  • Questions follow the latest CBSE competency-based pattern.

Q11. A mobile company wants to know customers’ opinions about a newly launched phone. It surveys 800 customers out of 2 lakh customers.

Question: Identify the method of data collection and justify your answer.
Answer:
Method: Sampling Method.
Justification: Only a representative part of the total customers is surveyed, saving time and cost.

Q12. A village has only 75 households. The government collects information from every household.

Question: Which method is used? Why is it suitable?
Answer:
Method: Census Method.
Reason: The population is small, so every household can be covered accurately.

Q13. A researcher selects respondents only from urban areas while studying the entire state’s literacy rate.

Question: Is the sample representative? Give a reason.
Answer:
No. Rural areas are excluded, making the sample biased and unrepresentative.

Q14. During quality control, a factory checks only 100 bulbs from a lot of 20,000 bulbs.

Question: Which method is being followed?
Answer:
Sampling Method, because only a selected number of bulbs are inspected.

Q15. A district administration wants exact information about all government schools.

Question: Which method should it use? Give one reason.
Answer:
Census Method, because complete information from every school is required.

Q16. A market research agency completes a consumer survey within three days using a small group of respondents.

Question: Why was Sampling Method appropriate?
Answer:
It saved time, reduced cost and provided quick results through a representative sample.

Q17. A researcher includes respondents of different age groups, income levels and regions while selecting a sample.

Question: What characteristic of a good sample is reflected here?
Answer:
The sample is representative because it includes different sections of the population.

Q18. A survey is conducted only among morning shoppers to understand the buying behaviour of all customers visiting a supermarket.

Question: Why may the conclusion be incorrect?
Answer:
The sample is biased because afternoon and evening shoppers are not included.

Q19. A university collects information from every student before introducing a new examination system.

Question: Identify the method used and state one benefit.
Answer:
Method: Census Method.
Benefit: It provides complete and highly accurate information.

Q20. A company wants quick feedback about a TV advertisement before launching it across the country.

Question: Which method is more suitable? Give one reason.
Answer:
Sampling Method because quick feedback can be obtained at a lower cost without surveying every consumer.

πŸ“˜ Class 11 Statistics for Economics
Chapter – Collection of Data
βœ… Part 5A – Case-Based Questions (1–5)

Instructions:
  • Read the case carefully.
  • Answer all the questions based on the given information.
  • Questions are based on the latest CBSE competency-based pattern.

Case Study 1 – School Health Survey

A school has 2,500 students. The principal wants to know the average height of students. Instead of measuring every student, 250 students are selected from different classes and their heights are recorded.

Q1. Which method of data collection has been used?
A. Census Method
B. Sampling Method
C. Observation Method
D. Interview Method

Q2. Why is this method suitable?
Answers:
  • Q1. B. Sampling Method
  • Q2. It saves time and cost while providing reliable results if the sample is representative.

Case Study 2 – Population Census

The Government conducts a nationwide population census and collects information from every household in the country.

Q1. Identify the method used.
A. Sampling Method
B. Census Method
C. Questionnaire Method
D. Observation Method

Q2. Mention one advantage of this method.
Answers:
  • Q1. B. Census Method
  • Q2. It provides complete and highly accurate information because every unit is covered.

Case Study 3 – Market Research

A company wants to launch a new soft drink. It surveys 800 customers selected from different cities before introducing the product.

Q1. Which method has the company adopted?
A. Census Method
B. Sampling Method
C. Population Method
D. Experimental Method

Q2. Why did the company not survey every customer?
Answers:
  • Q1. B. Sampling Method
  • Q2. Surveying every customer would be expensive and time-consuming.

Case Study 4 – Quality Inspection

A factory manufactures 40,000 LED bulbs every month. Before dispatch, only 500 bulbs are tested for quality.

Q1. Which method is used?
A. Census Method
B. Sampling Method
C. Interview Method
D. Observation Method

Q2. State one benefit of this method.
Answers:
  • Q1. B. Sampling Method
  • Q2. It reduces inspection time and cost while maintaining quality control.

Case Study 5 – Village Survey

A village has only 90 families. The local administration collects information from every family to prepare a development plan.

Q1. Which method is most appropriate?
A. Sampling Method
B. Census Method
C. Random Survey
D. Observation Method

Q2. Give one reason for using this method.
Answers:
  • Q1. B. Census Method
  • Q2. Since the population is small, every family can be covered accurately.

πŸ“˜ Class 11 Statistics for Economics
Chapter – Collection of Data
βœ… Part 5B – Case-Based Questions (6–10)

Instructions:
  • Read each case carefully.
  • Answer all the questions based on the information provided.
  • Questions follow the latest CBSE competency-based pattern.

Case Study 6 – Election Opinion Poll

Before the state elections, a survey agency interviews 5,000 voters selected from different districts instead of interviewing every voter in the state.

Q1. Which method of data collection is used?
A. Census Method
B. Sampling Method
C. Observation Method
D. Experimental Method

Q2. Why is this method suitable for election surveys?
Answers:
  • Q1. B. Sampling Method
  • Q2. It provides quick and economical results while representing different sections of voters.

Case Study 7 – Hospital Record Survey

A district hospital wants complete information about every patient admitted during the year. Therefore, records of all patients are examined.

Q1. Which method is used?
A. Sampling Method
B. Census Method
C. Interview Method
D. Observation Method

Q2. Why is this method appropriate?
Answers:
  • Q1. B. Census Method
  • Q2. Complete and accurate information about every patient is required.

Case Study 8 – Customer Satisfaction Survey

A supermarket interviews only customers visiting the store in the morning and concludes that all customers are satisfied with its services.

Q1. Is the conclusion reliable?
A. Yes, always
B. No, because the sample is biased
C. Yes, because morning customers represent everyone
D. None of these

Q2. Suggest one improvement in the survey.
Answers:
  • Q1. B. No, because the sample is biased.
  • Q2. Select customers from different time slots and different days to make the sample representative.

Case Study 9 – Agricultural Survey

A state government wants information about crop production. Instead of collecting data from every farmer, it selects farmers from different districts, villages and farm sizes.

Q1. Which method is being used?
A. Census Method
B. Sampling Method
C. Observation Method
D. Experimental Method

Q2. Why is this sample considered better?
Answers:
  • Q1. B. Sampling Method
  • Q2. It includes farmers from different regions and farm sizes, making the sample more representative.

Case Study 10 – University Feedback Survey

A university wants students’ opinions about a new online learning platform. It randomly selects 1,000 students from different departments and years of study.

Q1. Identify the method used.
A. Census Method
B. Sampling Method
C. Complete Enumeration
D. Observation Method

Q2. State one advantage of this method.
Answers:
  • Q1. B. Sampling Method
  • Q2. It provides reliable feedback in less time and at a lower cost than surveying every student.

πŸ“˜ Class 11 Statistics for Economics
Chapter – Collection of Data
βœ… Part 6A – Previous Year & CBSE PYQ Style Questions (1–5)

Note: These questions are based on the pattern of CBSE Previous Year Papers, CBSE Sample Papers and CBSE Question Bank.

PYQ 1 (2 Marks)

Differentiate between Census Method and Sampling Method on any two bases.

Answer:
BasisCensus MethodSampling Method
CoverageStudies every unitStudies selected units
Cost & TimeHighLow

PYQ 2 (3 Marks)

Explain any three advantages of the Sampling Method.

Answer:
  • Saves time.
  • Economical.
  • Suitable for large populations.

PYQ 3 (3 Marks)

State any three situations where the Census Method is preferred.

Answer:
  • When the population is small.
  • When complete accuracy is required.
  • When information from every unit is needed.

PYQ 4 (5 Marks)

Explain Population and Sample with suitable examples.

Answer:

Population: The complete set of units under investigation.

Example: All students of a school.

Sample: A representative part selected from the population.

Example: 200 students selected from the school for a survey.

PYQ 5 (5 Marks)

A researcher has limited time and funds to study the eating habits of students in a city. Which method of data collection should be adopted? Give reasons.

Answer:

Sampling Method should be adopted because:

  • It saves time.
  • It is economical.
  • It provides reliable results if the sample is representative.
  • It is suitable for a large population.

πŸ“˜ Class 11 Statistics for Economics
Chapter – Collection of Data
βœ… Part 6B – Previous Year & CBSE PYQ Style Questions (6–10)

Note: These questions are based on the latest CBSE Question Bank, Sample Papers and Previous Year examination pattern.

PYQ 6 (2 Marks)

Why is Sampling Method generally preferred over Census Method in large-scale investigations? Give any two reasons.

Answer:
  • It saves time.
  • It is economical and requires fewer resources.

PYQ 7 (3 Marks)

Explain any three characteristics of a good sample.

Answer:
  • It should be representative of the population.
  • It should be free from bias.
  • Its size should be adequate for the study.

PYQ 8 (3 Marks)

State any three limitations of the Census Method.

Answer:
  • It is expensive.
  • It requires more time.
  • It requires a large number of investigators and resources.

PYQ 9 (5 Marks)

Differentiate between Population and Sample with suitable examples.

Answer:
BasisPopulationSample
MeaningEntire group under studyRepresentative part of the population
SizeLargerSmaller
ExampleAll students of a school200 students selected from the school

PYQ 10 (5 Marks)

A company manufacturing mobile phones wants to know customers’ opinions about a new model. It has limited time and budget.

(a) Which method of data collection should the company use?

(b) Give any three reasons in support of your answer.

Answer:

(a) Sampling Method.

(b)

  • It saves time.
  • It reduces the cost of the survey.
  • It provides reliable results if the sample is representative of the population.

πŸ“ Interactive Quiz
Class 11 Statistics for Economics
Chapter – Collection of Data




πŸ“₯ Download Chapter Notes

Download the complete Class 11 Statistics for Economics – Collection of Data notes in PDF format for offline study.

πŸ“š This PDF Includes:

  • βœ… Complete NCERT Notes
  • βœ… Premium Mind Maps
  • βœ… Colourful Flow Diagrams
  • βœ… 50 CBSE MCQs with Answer Key
  • βœ… 20 Competency-Based Questions
  • βœ… 10 Case-Based Questions
  • βœ… CBSE PYQ Style Questions with Solutions
  • βœ… Interactive Quiz
  • βœ… Quick Revision Charts

πŸŽ‰ Best of Luck!

Practice regularly, revise the mind maps and solve all questions to score excellent marks in your CBSE Class 11 Statistics for Economics examination.

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