Research 3

convenience sampling

a group of elements that are readily accessible to the researcher

element

a kind of thing a researcher wants to sample

quota sampling

a nonprobability sampling procedure that involves describing target population in terms of what are thought to be relevant criteria and then selecting sample elements to represent the "relevant" subgroups in proportion to their presence in the target population, similar to stratified sampling

purposive sampling

a nonprobability sampling procedure that involves selecting elements based on the researcher's judgement about which elements will facilitate his or her investigation, when you need to know about a particular group

snowball sampling

a nonprobability sampling procedure that involves using members of the group of interest to identify other members of the group, good for when you have a hard to reach population

sample

a number of individual cases drawn from a larger population, who ends up being in your study

simple random sample

a probability sample in which every member of a study population has been given an equal chance of selection, the easiest and fastest

stratified sampling

a probability sampling procedure that involves dividing the population in groups defined by the presence of certain characteristics and then random sampling from each group

cluster sampling

a probability sampling procedure that involves randomly selecting clusters of elements from a population and subsequently selecting every element in each selected cluster for inclusion in the sample, used when data collection involves visits to sites that are far apart

systematic sampling

a probability sampling procedure that involves selecting every nth element from a list of population elements, after the first element has been randomly selected

multistage sampling

a probability sampling procedure that involves several stages, such as randomly selecting clusters from a population, then randomly selecting elements from each of the clusters

margin of error

a suggestion of how far away the actual population parameter is likely to be from the statistic

parameter

a summary of a variable characteristic in a population

statistic

a summary of a variable in a sample

coverage error

an error that results from differences between the sampling frame and the target population ex. the FDR election

nonresponse error

an error that results from people not responding

sampling error

any difference between sample characteristics and the equivalent characteristics in the sampling frame, when this difference is not due to nonresponse error

population

everyone that you want to generalize

probability samples

samples drawn in a way to give every member of the population a known chance of inclusion

biased samples

samples that are unrepresentative of the population from which they've been drawn

nonprobablilty samples

samples that have ben drawn in a way that doesn't give every member of the population a known chance of being selected

generalizability

the ability to apply the results of a study to groups or situations beyond those actually studied

selection interval

the distance between the element selected in a sample (N/n)

sampling distribution

the distribution of a sample statistic computed from many samples

sampling frame

the group of elements from which a sample is actually selected, ideally a list of everyone in the population

target population

the population of theoretical interest

sampling

the process of drawing a number of individual cases from a larger population

sampling variability

the variability in a sample statistics that can occur when different samples are drawn from the same population