Test 1: Sampling and Operational Definitions Flashcards
What are the probability sampling methods?
Simple random sample
Systematic sampling
Cluster sample
Stratified sample
How is a simple random sample acquired?
Selecting members through random lottery or draws
How is a systematic sample acquired?
Selecting members using a fixed, periodic interval (sampling interval)
How is a cluster sample acquired?
Selecting all members in randomly selected groups or clusters
How is a stratified sample acquired?
Randomly selecting members from each stratum in a population
What are the pros and cons of probability sampling?
Samples have a higher chance of representing the whole population, but not all selected subjects are necessarily willing to answer. Can be used to work with quantitative data
What are the non-probability sampling methods?
Convenience sampling
Voluntary sampling
Purposive sampling
Snowball sampling
How is a convenience sample acquired?
Selecting members through convenience (i.e.: proximity and availability)
How is a voluntary sample acquired?
Members volunteer to be in treatment or control group
How is a purposive sample acquired?
Using judgement to select members that are most useful for the study
How is a snowball sample acquired?
Asking early participants to recruit more members of the sample
What are the pros and cons of non-probability sampling?
Participants are easier to access, but have a higher risk of presenting a sampling bias. Should be used for exploratory and qualitative research and not make statistical inferences
What are the concepts that an operational definition should be?
Accurate, precise, and reliable
Def. of accurate
Measurements must approximate a “true value”, and be as close to it as possible
Def. of precise
Standards are consistently reproducible, measurements are generally close to each other, even if not accurate
Def. of reliable
Measurements have been tested and are considered trustworthy
What is an operational definition?
The transformation of an abstract, theoretical concept into something more concrete, observable, and measurable in an empirical research project
Example
Temperature: actual vs. operational definitions
Actual definition of temperature: the degree of hotness or coldness as measured on a definite temperature scale
Operational definition: degrees Celsius measured by a mercury-in-glass clinical thermometer
Example
Intelligence: actual vs. operational definitions
Actual definition of intelligence: the ability to learn, understand, or deal with new situations
Operational definition: the skills and abilities measured by a fourth edition Stanford Binet Intelligence Test
