sampling Flashcards
(20 cards)
What is a sample?
A subset, or some part, of a larger population.
Samples are used to draw conclusions about the entire population without needing to collect data from every individual.
Define population in the context of sampling.
Any complete group of entities that share some common sets of characteristics.
Understanding the population is crucial for effective sampling.
What is a population element?
An individual member of a population.
Each element contributes to the overall characteristics of the population.
What is a census?
An investigation of all the individual elements that make up a population.
A census can be resource-intensive and time-consuming.
List reasons why sampling is often more beneficial than a census.
- Practicality
- Cost-effectiveness
- Time-saving
- Feasibility in large populations
What is the target population?
The relevant population that should be included for data collection.
Operationally defining the target population helps in identifying ideal data-collection sources.
What is a sampling frame?
A mechanism for defining which elements from a target population are available for selection.
It is also known as the working population.
What is a sampling frame error?
Occurs when certain sample elements are not listed or accurately represented in a sampling frame.
This can lead to biased results if important elements are missing.
Define sampling unit.
A single element or group of elements subject to selection in the sample.
Sampling units can be individuals, groups, or even entire entities.
True or False: Non-response error can cause a sample to be less than perfectly representative.
True.
Non-response error occurs when certain groups do not participate in the survey.
What differentiates probability sampling from non-probability sampling?
Probability sampling has a known, non-zero probability of selection for each member of the population, while non-probability sampling relies on personal judgment or convenience.
This distinction affects the accuracy and reliability of the results.
What is random sampling error?
A statistical fluctuation that occurs because of chance variations in the elements selected for a sample.
It generally decreases as sample size increases.
Fill in the blank: A _______ error occurs due to imperfect sample design.
systematic (non-sampling) error.
This type of error is often more difficult to quantify than random sampling error.
What factors should be considered when determining sample size?
- Required level of accuracy
- Cost-benefit analysis
- Population variability
- Time and budget constraints
What is the impact of larger sample sizes on accuracy?
Larger sample sizes increase accuracy and decrease random sampling error.
However, the rate of decrease in sampling error slows as sample size increases.
What is the importance of mobile devices and the Internet in sampling?
They change many standard sampling methods, allowing for new ways of collecting data.
Internet surveys can reach broader populations more efficiently.
What is respondent-driven sampling?
where existing study subjects recruit future subjects from among their acquaintances.
This method can help access hard-to-reach populations.
In the context of sampling, what are the key takeaways regarding why sampling is done?
- Pragmatic reasons
- Accurate and reliable results
- Cost reduction
- Feasibility in accessing total population
What type of sampling procedure is used when a researcher asks one participant to refer others?
Snowball sampling.
This method is useful for reaching hidden populations.
What is the main difference between random sampling error and systematic (non-sampling) error?
Random sampling error is due to chance fluctuations, while systematic error is due to imperfect sample design.
Understanding these errors is crucial for data interpretation.