Learning Objectives

By the end of this lesson, learners should be able to:

  • Define population and sample.
  • Explain why sampling is used in business research.
  • Distinguish between census and sample surveys.
  • Identify sampling units and sampling frames.
  • Recognize sampling error and non-sampling error.

Meaning Of Population

A population is the complete set of individuals, organizations, transactions, or objects that a researcher wants to study.

Business Examples

  • All customers of a global e-commerce company,
  • All employees of a multinational bank,
  • All hotel guests in a hospitality chain,
  • All transactions processed during a quarter.

The population must be clearly defined before any data collection begins.

International Example

A telecommunications company operating in Canada, United Kingdom, India, South Africa, and Australia wants to measure customer satisfaction. The population is all active customers across these countries.

Meaning Of A Sample

A sample is a subset of the population selected for study. Researchers analyze the sample and use the findings to understand the population.

Example

From a population of 2 million customers, the company surveys 5,000 customers.

Why Sampling Is Used

Collecting data from every customer would be extremely expensive, time-consuming, and operationally difficult. Sampling provides a practical alternative.

Census Vs Sample Survey

Aspect

Census

Sample Survey

Coverage

Entire population

Subset of population

Cost

Very high

Lower

Time

Longer

Faster

Accuracy

Potentially very high

Depends on sampling quality

Example

National population census

Customer satisfaction survey

A census is justified only when the population is small or when complete accuracy is essential.

Sampling Unit

The sampling unit is the basic element selected during sampling.

Examples

  • Individual customer,
  • Household,
  • Retail store,
  • Bank branch,
  • Employee.

The sampling unit should match the research objective.

Sampling Frame

A sampling frame is the list or database from which the sample is selected.

Examples

  • Customer database,
  • Employee payroll system,
  • Membership registry,
  • Supplier list.

A good sampling frame should be complete, accurate, current, and free from duplicates.

Common Problems

  • Missing records,
  • Outdated contact details,
  • Duplicate entries,
  • Ineligible members.

Why Sampling Is Important In Business Analytics

Sampling supports:

Faster Decision-Making

Managers receive results more quickly.

Cost Efficiency

Research budgets are reduced substantially.

Operational Feasibility

Large international populations can be studied.

Improved Data Quality

Smaller datasets can be monitored more carefully.

Frequent Measurement

Organizations can conduct regular customer or employee surveys.

Sampling Error

Sampling error is the difference between a sample result and the true population value that occurs because only part of the population is observed.

Example

Population satisfaction = 82%
Sample satisfaction = 80%

Sampling error = −2 percentage points.

Sampling error decreases when sample size increases.

Non-Sampling Error

Non-sampling errors are not caused by sample selection.

Examples

  • Respondent misunderstanding,
  • Data entry mistakes,
  • Interviewer bias,
  • Nonresponse,
  • Poor questionnaire wording.

Non-sampling errors can be more serious than sampling error.

Representativeness

A representative sample reflects the important characteristics of the population, such as age, gender, region, income level, or customer segment.

Example

If 40% of customers are in Europe, the sample should contain approximately 40% European customers unless another design is intentionally used.

Business Case Study: International Retailer

A retailer with stores in New York, London, Berlin, Dubai, Singapore, and Sydney wants customer feedback.

Poor Sample

Surveying only customers who visit the flagship London store.

Better Sample

Selecting customers from all regions in proportion to sales volume.

The second approach produces more reliable international insights.

Practical Activity

Define the population, sampling unit, and sampling frame for each of the following:

  1. Employee engagement study,
  2. Online customer satisfaction survey,
  3. Supplier performance evaluation,
  4. Hotel guest experience survey.

Learning Materials / Reference Materials

Core Textbooks

  • Malhotra, N. Marketing Research.
  • Saunders, Lewis & Thornhill. Research Methods for Business Students.

International Resources

  • AAPOR Survey Basics.
  • ESOMAR Research Standards.
  • OECD Survey Methodology Resources.

Lesson Summary

Sampling allows organizations to study large populations efficiently. Clear definition of the population, sampling unit, and sampling frame is essential for reliable business research.

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