Unit 9: Sampling in Research Flashcards
population is ____ restricted to human subjects
not
eligibility criteria
the criteria used to designate the specific attributes of the target population, and by which people are selected for particpation
the target population
is the entire population in which a researcher is interested
accessible population
comprises cases from the target population that are accessible to the researcher as a pool of subjects
sampling
is the process of selecting a portion of the population to represent the entire population
sample
is a subset of the population
elements
the entities that make up the samples and population
sampling bias
is the systematic over-representation or under-representation of some segments of the population in terms of a characteristic relevant to the research questions
strata
are mutually exclusive segments of a population
nonproability sampling
used in quantitative research. use three methods convenience, quota and purposive
convenience sampling
entails using the most conveniently available people as participants
snowball sampling
a type of convenience sampling when early sample members are asked to refer others who meet eligibility criteria
quota sampling
researcher identify strata of the population and hen determine how man participants are needed from each stratum to meet a quota
purposive sampling
is based on the belief that researchers’ knowledge about the population can be used to hand pick the cases to be included in the sample
advantages of non-probability
convenient and cost effective
probability sampling
involves random selection of elements from the population
random selection
process is one in which each element int he population has an equal, independent chance of being selected
simple random sampling
more complex probability sampling designs incorporates features of simple random sampling, the procedures are briefly described so that you can understand what is involved
sampling frame
the technical name for the actual list of population elements
stratified random sampling
he population is divided into homogeneous subset from which elements are selected at random
cluster sampling
there is a successive random sampling of units
systemic sampling
involves the selection of every kth case from a list of group such as every 100th person on a patient list
sampling error
is the diff between population values and sample values
power analysis
a procedure for estimating either the likelihood of committing a type II error or sample size requirement
types of qualitative sampling
convenience and snowball sampling
» volunteer sample
purposive sampling
» max variation sampling-involves purposefully selecting cases with a range of variation on dimension of interest
»homogeneous sampling involves a deliberate reduction of variation to permit a more focused inquiry
» extreme deviant care sampling provides opportunities for learning from the most usual and extreme informants
»typical case sampling involves selecting participant who will illustrate or highlight what is typical or average
Theoretical sampling- is a method of sampling used in a grounded theory study defined this sampling approach as “the process of data collection for generating theory where by the analyst jointly collects, codes, and analyzes his data and decided what data to collect next and where to find them, in order to develop his theory as it emerges
ethno
make numerous sampling decisions these decisions are often aided by key informants who serve as guides and interpreters
phenomenlogist
typically work with a small sample of people who met the criteria of having lived the experience under study
GT
uses theoretical sampling and work with samples of about 20 to 30 people
