Exam 2 - Chapter 9 Flashcards
what is a sample?
the people / elements that researchers collect data from
define population
a particular group of individuals or elements that are the focus of the research
what are the components of a population?
- target population
- accessible population
- sample
- element
what is target population?
an entire set of individuals or elements who meet the sampling criteria
what is accessible population?
a portion of the target population to which the researcher has access
what is an element?
individual units of the population and sample
what is sampling?
a subset of a population selected to represent the whole population
what does a sampling plan / method define?
the selection process which researchers use to choose the subjects or participants
define generalization
the act of extending the findings from the sample study to the larger population
what are the qualities that influence the extent of generalization?
- quality of the study
- consistency of findings
define inclusion criteria
characteristics that subjects must have to be part of the target population
define exclusion criteria
characteristics a person or an element has that causes them to be excluded from the study
what are the types of samples?
- homogenous
- heterogeneous
homogenous sampling is narrowly defined
true
what does homogenous sampling limit?
generalization of findings
what does heterogenous sampling allow researchers to have?
a broad range of values being studied
what does heterogenous sampling entail?
- increased representativeness of the sample
- ability to generalize
define representativeness
the sample, access population, and target population are all alike in many ways
what is a representative sample?
a sample that has members who have characteristics similar to those of the population from which it was drawn
what is a sampling error?
the difference between population mean and sample mean
how does random variation occur?
it happens by chance
different values were drawn from the same sample
how does systematic variation occur?
occurs deliberately by careful selection of subjects whose values differ specifically from the population
systematic variation is a result of bias
true
define refusal rate
the percentage of subjects who declined to participate in the study
define acceptance rate
the percentage of subjects who consented to participate
what is a sample attrition?
the withdrawal or loss of subjects from a study
high attrition rates results to an invalid study
true
what is a sample retention?
the number of subjects who remain in and complete a study
what is a sampling frame?
a listing of every member of the population
how is the sampling frame formed?
by using the sampling criteria to define membership in the population
what is a sampling plan?
an outline of strategies used to obtain a sample for a study
what are the types of sampling plans?
- probability
- nonprobability
what does probability sampling entail?
each person or element in a population has an opportunity to be selected for a sample
how can probability sample be achieved?
through random selection
the opportunity for systematic bias is less when participants are selected randomly
true
what are the types of probability sampling?
- simple random sampling
- stratified random sampling
- cluster sampling
- systematic sampling
what is simple random sampling?
the most basic of the probability sampling plans
how can simple random sampling be achieved?
by randomly selecting elements from the sampling frame
in what situation is stratified random sampling used?
when the researcher knows some of the variables in the population are important for representativeness
what are examples of variables used in stratification?
- diagnosis
- age
- gender
- race
- socioeconomic status
when is cluster sampling best used?
- it is necessary to obtain a geographically dispersed sample
- the researcher cannot identify the individual elements (unable to develop a sampling frame)
what does cluster sampling entail?
a list of all states, cities, institutions, or clinicians that elements of the identified population can be linked with
what does systematic sampling entail?
an ordered list of all members of the population is available
what is the process involved with systematic sampling?
selecting every kth individual on the list, with a starting point randomly selected
what does it mean if the starting point is not random?
the sample is a nonprobability or nonrandom sample
what does nonprobability sampling entail?
not every element of a population has an opportunity to be selected for a study sample (least likely to be generalized)
why is nonprobability sampling most commonly used in nursing research?
this type of sampling reduces representativeness of a target population (there are a limited number of patients available for research)
what are the types of nonprobability sampling?
- convenience sampling
- quota sampling
- purposive sampling
- network sampling
- theoretical sampling
what does convenience sampling entail?
- provides little opportunity to control biases
- opportunistic in selecting participants for a study
accidental sampling
what are characteristics of convenience sampling?
- inexpensive
- accessible
- less time-consuming
what can convenience sampling provide in research?
a means to conduct studies on nursing interventions when researchers cannot use probability sampling methods
what does quota sampling entail?
ensures the inclusion of participant types likely to be underrepresented in the convenience sample
what does purposeful sampling entail?
researcher consciously selects their sample to include in the study
what does network sampling entail?
locating participants for a study is difficult & thus takes advantage of social networks
what is network sampling most useful for?
findings participants from socially devalued populations
what is theoretical sampling used for?
developing a selected theory or model
what are the characteristics of the data that theoretical sampling needs?
- generates
- delimits
- saturates
theoretical codes in the study needed for theory generation
how does saturation occur?
when additional sampling provides no new information
define effect size
the extent to which the null or statistical hypothesis is false
