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Questions and Answers
What is meant by 'Population' in sampling terminology?
What is meant by 'Population' in sampling terminology?
Which of the following statements about samples is true?
Which of the following statements about samples is true?
What is a 'sampling frame'?
What is a 'sampling frame'?
Why might researchers choose to use sampling instead of a full census?
Why might researchers choose to use sampling instead of a full census?
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What would constitute a 'census' in sampling terminology?
What would constitute a 'census' in sampling terminology?
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What is a key benefit of sampling in research?
What is a key benefit of sampling in research?
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What type of sampling technique guarantees that every member of the population has a known, nonzero probability of selection?
What type of sampling technique guarantees that every member of the population has a known, nonzero probability of selection?
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Which of the following best explains the concept of 'population element'?
Which of the following best explains the concept of 'population element'?
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Which sampling method involves selecting units based on convenience?
Which sampling method involves selecting units based on convenience?
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What type of sampling ensures representation of various subgroups to the desired extent by the investigator?
What type of sampling ensures representation of various subgroups to the desired extent by the investigator?
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What are 'strong similarities in population elements' important for in sampling?
What are 'strong similarities in population elements' important for in sampling?
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Systematic errors associated with the sampling process can lead to a sample that is:
Systematic errors associated with the sampling process can lead to a sample that is:
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In which type of sampling is the probability of selection for a member of the population unknown?
In which type of sampling is the probability of selection for a member of the population unknown?
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Judgment sampling is also known as which type of sampling?
Judgment sampling is also known as which type of sampling?
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Which sampling method limits selection based on an individual's convenience, potentially introducing bias?
Which sampling method limits selection based on an individual's convenience, potentially introducing bias?
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A sampling technique where an experienced individual selects sample members based on their judgment is called:
A sampling technique where an experienced individual selects sample members based on their judgment is called:
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What is a significant advantage of quota sampling over probability sampling?
What is a significant advantage of quota sampling over probability sampling?
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Which type of sampling ensures each element in the population has an equal chance of being included in the sample?
Which type of sampling ensures each element in the population has an equal chance of being included in the sample?
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What is the main disadvantage of nonprobability sampling methods like quota sampling?
What is the main disadvantage of nonprobability sampling methods like quota sampling?
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What is the primary characteristic of snowball sampling?
What is the primary characteristic of snowball sampling?
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What is the primary sampling unit in cluster sampling?
What is the primary sampling unit in cluster sampling?
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In proportional stratified sampling, how are sampling units drawn from each stratum?
In proportional stratified sampling, how are sampling units drawn from each stratum?
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Which sampling technique combines two or more probability sampling methods?
Which sampling technique combines two or more probability sampling methods?
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What is one potential source of bias in nonprobability sampling methods?
What is one potential source of bias in nonprobability sampling methods?
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Disproportional stratified sampling allocates sample size based on what criteria?
Disproportional stratified sampling allocates sample size based on what criteria?
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What is typically the first step in multistage area sampling?
What is typically the first step in multistage area sampling?
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What is a common characteristic of systematic sampling?
What is a common characteristic of systematic sampling?
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What characterizes internet sampling as described in the content?
What characterizes internet sampling as described in the content?
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Which factor does NOT affect the choice of the appropriate sample design?
Which factor does NOT affect the choice of the appropriate sample design?
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What is a characteristic of panel samples in internet sampling?
What is a characteristic of panel samples in internet sampling?
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What is one potential issue with using opt-in lists in internet sampling?
What is one potential issue with using opt-in lists in internet sampling?
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In cluster sampling, how are clusters selected?
In cluster sampling, how are clusters selected?
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What does sampling frame error refer to?
What does sampling frame error refer to?
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What is a Primary Sampling Unit (PSU)?
What is a Primary Sampling Unit (PSU)?
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Which of the following best describes random sampling error?
Which of the following best describes random sampling error?
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Which type of error results from nonsampling factors?
Which type of error results from nonsampling factors?
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What does a reverse directory contain?
What does a reverse directory contain?
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What is the key purpose of sampling services or list brokers?
What is the key purpose of sampling services or list brokers?
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Which selection stage follows the Primary Sampling Unit (PSU)?
Which selection stage follows the Primary Sampling Unit (PSU)?
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What primarily causes random sampling error?
What primarily causes random sampling error?
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Study Notes
Sampling Terminology
- Population (universe): Any complete group of entities sharing common characteristics.
- Population Element: An individual member of a population.
- Census: An investigation of all population elements.
- Sample: A subset of a larger population.
Why Sample?
- Pragmatic Reasons: Budget and time constraints, limited population access.
- Accurate and Reliable Results: Samples can provide reasonably accurate information. Strong similarities in population elements make sampling possible. It may be more accurate than a census.
- Destruction of Test Units: Sampling reduces research costs in finite populations.
Stages in the Selection of a Sample
- Define the target population.
- Select a sampling frame.
- Determine probability or nonprobability sampling method.
- Plan procedure for selecting sampling units.
- Determine sample size.
- Select actual sampling units.
- Conduct fieldwork.
Practical Sampling Concepts
- Defining the Target Population: Identification of the relevant population and individuals to be studied, specifying and defining their characteristics precisely.
- The Sampling Frame: A list of elements from which to draw a sample (also called the working population).
- Sampling Frame Error: Occurs when sample elements are missing or inaccurately represented in the sampling frame.
Practical Sampling Concepts (continued)
- Sampling Services (list brokers): Provide lists/databases of names, addresses, phone numbers, and email addresses.
- Reverse Directory: A directory similar to a phone directory but organized by address or phone number instead of alphabetically by name.
Sampling Units
- Sampling Unit: A single element or group of elements selected for the sample.
- Primary Sampling Unit (PSU): The unit selected in the first stage of sampling.
- Secondary Sampling Unit: The unit selected in the second stage of sampling.
- Tertiary Sampling Unit: The unit selected in the third stage of sampling.
Random Sampling and Nonsampling Errors
- Random Sampling Error: The difference between sample results and a census using identical procedures. A statistical fluctuation due to chance variations.
- Systematic Sampling Error (nonsampling error): Error arising from factors other than simple sampling, focusing on study design and execution accuracy, not random chance fluctuation.
Random Sampling and Nonsampling Errors (continued)
- Less than Perfectly Representative Samples: Random and systematic errors in a sampling process combine, yielding an imperfect sample representation of the population.
Errors Associated with Sampling
- Visual representation of sampling frame error, random sampling error, and non-response error. The intended sample vs the actual sample.
Probability versus Nonprobability Sampling
- Probability Sampling: Every member of the population has a known, non-zero probability of selection.
- Nonprobability Sampling: Sample units are selected based on personal judgment or convenience; the probability of any one member being selected is unknown.
Nonprobability Sampling
- Convenience Sampling: Choosing readily available subjects.
- Judgment (Purposive) Sampling: An experienced individual handpicks the sample based on relevant characteristics.
- Quota Sampling: Guaranteeing proportionality of subgroups within a population of interest.
Nonprobability Sampling (continued)
- Possible Sources of Bias: Respondents selected due to similarities with the interviewer, ease of access, willingness to participate, or specific demographic characteristics (e.g., middle-class).
- Advantages of Quota Sampling over Probability Sampling: Faster data collection, lower costs, and convenience.
- Snowball Sampling: Initial respondents identify further participants based on provided information.
Probability Sampling
- Simple Random Sampling: Every population member has an equal chance of inclusion.
- Systematic Sampling: A random starting point on a list, and every nth member from that point is selected.
- Stratified Sampling: Creating simple random subsamples with relatively equal characteristics within each stratum of the population.
Proportional versus Disproportional Sampling
- Proportional Stratified Sample: The number of sampling units from each stratum is directly proportional to the population size within that stratum.
- Disproportional Stratified Sample: Sampling sizes for strata are allocated according to analytical needs or considerations.
Cluster Sampling
- Cluster Sampling: An effective sampling method where the primary sampling unit is a complete cluster of elements, not individual elements. Clusters are selected randomly.
Multistage Area Sampling
- Multistage Area Sampling: Combining multiple probability sampling techniques, typically involving progressively smaller geographic areas until a housing unit is selected (e.g., from a city-to-block-to-household level).
What is the Appropriate Sample Design?
- Degree of accuracy required, available resources, time constraints, advanced knowledge of the population, national versus local projects.
Internet Sampling is Unique
- Website Visitors: Internet surveys utilize unrestricted sampling methods, often not representative of the actual population.
- Panel Samples, Recruited Ad Hoc Samples, Opt-in Lists: These are specific internet-based sampling techniques.
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Description
This quiz explores the fundamental terminology and concepts of sampling in research. Learn about populations, samples, and the importance of sampling methods in obtaining accurate results. Test your understanding of the various stages involved in selecting a sample and practical sampling concepts.
