Lecture 3

Question 1

Bias Selection

Answer 1

• Deliberately or purposively selecting a “representative” sample
• Not specifying the target population
• Failing to include all of the target population in the sampling frame (Undercoverage)
• Including population units in the sampling frame that are not in the target population (Overcoverage)
• Having multiplicity of listings in the sampling frame
• Substituting a convenient member of a population for the designated member who is not readily available
• Failing to obtain responses from all the chosen sample (Non-responses)
• Allowing the sample to consist entirely of all volunteers

Question 2

Advantage of Sampling Over Complete Enumeration

Answer 2

• Less Labor
• Reduced Cost
• Greater Speed
• Greater Scope
• Greater Efficiency and Accuracy
• Convenience
• Ethical Considerations

Question 3

Sampling Procedure

Answer 3

• Identify the population
• Determine if the population is accessible
• Select a sampling method
• Choose a sample that is representative of the population
• Ask the question, can I generalize to the general population from the accessible population

Question 4

Cases where Non-Probability Sampling is Useful

Answer 4

• Only few are willing to be interviewed
• Extreme difficulties in locating or identifying subjects
• Probability sampling is more expensive to implement
• Cannot enumerate the population elements

Question 5

Sources of Non-Sampling Error

Answer 5

• Non-responses
• Interview Error
• Misrepresented Answers
• Data entry errors
• Questionnaire Design
• Wording of Questions
• Selection Bias

Question 6

Probability Sampling Methods

Answer 6

• Simple Random Sampling
• Systematic Random Sampling
• Stratified Random Sampling
• Cluster Sampling
• Multi-Stage Sampling

Question 7

Non-Probability Sampling Methods

Answer 7

• Accidental Sampling
• Quota Sampling
• Convenience Sampling
• Purposive Sampling
• Judgement Sampling