Sampling

Sampling

1. Population

   • Target Population
   • Accessible Population

2. Types of Samples

   • Representative Sample
   • Biased Sample

3. Probability Sampling Methods

   • Probability Sampling
     • Entire Population Known
     • Random Process
     • Specifiable Probability of Selection
   • Simple Random Sampling
     • Clearly Identified Population
     • Random Selection
     • Sampling With/out Replacement
     • Larger Sample/Less Bias
   • Systematic Sampling
     • Selecting nth After Random Start
     • Less Random - Not all Participants can be Selected
       • Violated Principle of Independence
   • Stratified Random Sampling
     • Population in Strata/Subgroup
     • Compare Subgroups
   • Proportionate Stratified Random Sampling
     • Identifying Set of Subgroups
       • Determine Proportion in Population
         • Obtain Samples to Match Population
   • Cluster Sampling
     • Selects Units of Interest

4. Non-Probability Sampling Method

   • Types
     • Convenience Sampling
       • Availability
       • Strongly Biased
     • Quota Sampling
       • Define Subgroups
         • Establish Number of Individuals Needed in Each
           • Convenience Sample More Representative
     • Purposeful Sampling
       • Small Cases/Qualitative Research
       • Goal Not to Generalise
   • Population Not Known
   • Individual Probabilities Cannot be Known
   • Sampling based on Common Sense

5. Non-Sampling Error (Measurement Error)