List of the elements in your population and from this your sample is drawn
SAMPLING FRAME
Involves problems in your sampling, which reveals that your sample is not representative of your population
SAMPLING BIAS
Plan you set forth to be sure that the sample you use in your research study represents the population from which you drew your sample
SAMPLING TECHNIQUE/SAMPLING STRATEGIES
Samples obtained using objective chance mechanism
PROBABILITY SAMPLES
Advantage of Sampling Over Complete Enumeration
- Less Labor
- Reduced Cost
- Greater Speed
- Greater Scope
- Greater Efficiency and Accuracy
- Convenience
- Ethical Considerations
Samples are obtain haphazardly, selected purposively, or are taken as volunteers
NON-PROBABILITY SAMPLES
Steps in Sampling Procedure
- Identify population
- Determine if population is acceSsible
- Select 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?”
Most basic method of drawing a probability sample
SIMPLE RANDOM SAMPLING
Obtained by selecting every kth individual from the population
SYSTEMATIC RANDOM SAMPLING
Obtained by separating the population into non-overlapping groups called strata and then obtaining a simple random sample from each stratum
STRATIFIED RANDOM SAMPLING
Take the sample from naturally occurring groups in your population (heterogenous within cluster, homogenous among cluster)
CLUSTER SAMPLING
Selection of sample is done in two or more steps or stages with sampling units varying in each stage
MULTI-STAGE SAMPLING
Steps in Obtaining a Multi-Stage Sampling
- Organizing the sampling process into stages where the unit of analysis is systematically grouped
- Select a sampling technique for each stage
- Systematically apply the sampling technique to each stage until the unit of analysis has been selected
Basic Sampling Techniques of Non-Probability Sampling
- Accidental Sampling
- Quota Sampling
- Convenience Sampling
- Purposive Sampling
- Judgement Sampling
Cases wherein Non-Probability Sampling is Useful
- 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
Errors that result from the survey process
NON-SAMPLING ERROR
Error that results from using sampling to estimate information regarding a population
SAMPLING ERROR
Sources of Non-Sampling Error
- Non-responses
- Interviewer Error
- Misrepresented Answers
- Data entry errors
- Questionnaire Design
- Wording of Questions
- The order of the questions, words, and
responses
