Sociology Chapter 5

Census

Research in which information is obtained through responses from or information about all available members of an entire population

proportionate stratified sampling

Sampling method in which elements are selected from strata in exact proportion to their representation in the population

Representative sample

a sample that "looks like" the population from which it was selected in all respects that are potentially relevant to the study. The distribution of characteristics among the elements of a representative sample is the same as the distribution of those characteristics among the total population.

Probability sampling method

a sampling method that relies on a random, or chance, selection method so that the probability of selection of population elements is known

Target population

a set of elements larger than or different from the population sampled and to which the researcher would like to generalize study findings

Sample

a subset of a population that is used to study the population as a whole

Random number table

a table containing lists of numbers that are ordered solely on the basis of chance; it is used for drawing a random sample.

Enumeration units

units that contain one or more elements and that are listed in a sampling frame

Sample Size considerations

-the less sampling error desired, the larger the sample size must be -samples of more homogenous populations can be smaller than samples of diverse populations -strong relationships, you can use smaller sample sizes, weak relationships, use larger sample sizes

Simple random sampling

A method of sampling in which every sample element is selected only on the basis of chance, through a random process

Periodicity

A sequence of elements (in a list to be sampled) that varies in some regular, periodic pattern

systematic bias

Over representation or under representation of some population characteristics in a sample due to the method used to select the sample. A sample shaped by systematic sampling error is a biased sample.

Population

The entire set of individuals or other entities to which study findings are to be generalized

Random digit dialing

The random dialing by a machine of numbers within designated phone prefixes, which creates a random sample for phone surveys

purposive sampling

a nonprobability sampling method in which elements are selected for a purpose, usually because of their unique position. Ex: -knowledgeable about cultural arena or situation being studied -willing to talk -representative of the range of points of view

Sampling Frame

a list of all elements or other units containing the elements in a population

Inferential statistics

a mathematical tool for estimating how likely it is that a statistical result based on data from a random sample is representative of the population from which the sample is assumed to have been selected.

Replacement sampling

a method of sampling in which sample elements are returned to the sampling frame after being selected, so they may be sampled again. Random samples may be selected with or without replacement.

Snowball sampling

a method of sampling in which sample elements are selected as they are identified by successive informants or interviewees

Systematic random sampling

a method of sampling in which sample elements are selected from a list or from sequential flies.

Stratified random sampling

a method of sampling in which sample elements are selected separately from population strata that are identified in advance by the researcher

Random sampling

a method of sampling that relies on a random. or chance, selection method so that every element of the sampling frame has a known probability of being selected.

cluster

a naturally occurring, mixed aggregate of elements of the population

Quota sampling

a nonprobability sampling method in which elements are selected to ensure that the sample represents certain characteristics in proportion to their prevalence in the population.

Sampling error

any difference between the characteristics of a sample and the characteristics of a population. The larger the sampling error, the less representative the sample

Random sampling error (chance error)

differences between the population and the sample that are due only to chance factors (random error), not to systematic sampling error. Random sampling error may or may not result in an unrepresentative sample. The magnitude of sampling error due to chance factors can be estimated statistically

Nonrespondents

people or other entities who do not participate in a study although they are selected for the sample.

disproportionate stratified sampling

sampling in which elements are selected from strata in different proportions from those that appear in the population.

cluster sampling

sampling in which elements are selected in two or more stages, with the first stage being the random selection of naturally occurring clusters and the last stage being the random selection of elements within clusters

Availability sampling

sampling in which elements are selected on the basis of convenience

Non-probability sampling method

sampling method in which the probability of selection of population elements is unknown

Sampling units

units listed at each stage of a multistage sampling design

Unrepresentative sample

some characteristics are overrepresented or underrepresented.

Elements

the individual members of the population whose characteristics are to be measured

Probability of selection

the likelihood that an element will be selected from the population for inclusion in the sample. Ex: probability of selection for each element by tossing a coin is .5

Sampling interval

the number of cases from one sampled case to another in a systematic random sample

Sample statistic

the value of a statistic, such as a mean, computed from sample data.

population parameter

the value of a statistic, such as a mean, computed using the data for the entire population; a sample statistic in an estimate of a population parameter