Business Research Methods Session 4

Sampling vs. Census

• Population: Entire group of individuals or items targeted for study (e.g., all employees in a company).
• Population Parameter: Numerical value describing a characteristic of the population (e.g., average age of employees).
• Census: Data collection from every population member (e.g., national census collecting data from all residents).
• Sample: Subset of the population selected for study (e.g., surveying 200 out of 2,000 employees).
• Statistics: Numerical values calculated from a sample to estimate population parameters (e.g., average age of surveyed employees).

Conditions Favoring Sampling vs. Census

• Budget: Sampling is better for small budgets, while a large budget favors census.
• Time Available: Sampling requires less time; census requires longer duration.
• Population Size: Sampling is preferred for large populations; census for smaller populations.
• Variance in Characteristics: Sampling is suitable for low variance; census for high variance.
• Cost of Sampling Errors: Low in sampling; high in census.
• Cost of Nonsampling Errors: High in sampling; low in census.
• Nature of Measurement: Destructive measurements favor sampling; nondestructive measurements favor census.
• Attention to Individual Cases: Individual cases can be assessed in sampling; not in census.

Sampling Process

• Sampling Definition: Selecting a subset from a larger population to infer characteristics of the whole.
• Market Research and Sampling: Used to gauge consumer opinions and predict market trends.
• Health Research: Sampling helps understand disease prevalence in communities.
• Quality Control: Samples assess product quality from production batches.
• Political Polls: Sampling predicts election outcomes based on voter interviews.

Sampling Design Process

• Define the Target Population: Clarify elements, sampling units, extent, and time for data collection.
  • Element: Object of interest (e.g., a female customer aged 18 who buys Revlon lipstick).
  • Sampling Unit: Unit from which data is collected (e.g., a group of female customers aged 18-35).
  • Extent: Scope considering geographical and temporal aspects (e.g., U.S. customers over the past year).
  • Time: Specific period for data collection (e.g., a six-month survey).

Determining Sample Size

• Qualitative factors include:
  • Importance of decision-making.
  • Nature of research and variables involved.
  • Completion rates and resource constraints.
• Sample Sizes in Various Studies:
  • Problem identification research: Minimum size 500, typical range 1,000–2,500.
  • Problem-solving research: Minimum 200, typical range 300–500.
  • Focus groups: Minimum 2 groups, typical range 6–15 groups.

Sampling Frames

• Definition: Set of population elements represented in list form.
• Error Management: Can occur through omission or inclusion of irrelevant elements; addressed by refining the target population or screening respondents.

Classification of Sampling Techniques

• Convenience Sampling: Selects respondents based on their availability (e.g., random people in a mall).
• Judgmental Sampling: Selection based on researcher’s judgment (e.g., specific department stores).
• Quota Sampling: Requires control categories; elements are chosen based on convenience or judgment.
• Snowball Sampling: Initial groups refer others in the target population for selection.

Types of Probability Sampling

• Simple Random Sampling: Every population element has an equal chance of selection; independent selections.
• Systematic Sampling: Uses a random starting point and selects every ith element; effective for certain ordered populations.
• Stratified Sampling: Divides the population into strata for better representation; may use proportionate or disproportionate sampling.

Applications of Stratified Sampling

• Customer Satisfaction Surveys: Ensures diverse feedback by sampling across age groups.
• Employee Engagement Studies: Gathers input from various departments to reflect unique experiences.

This quiz focuses on Sampling and Data Preparation as part of Business Research Methods. It covers key concepts such as population, sampling, and census, providing essential knowledge for conducting effective research. Test your understanding of these foundational topics in research methodology.