Chapter 5

Question 1

Population

Answer 1

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

Question 2

Sample

Answer 2

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

Question 3

Elements

Answer 3

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

Question 4

Sampling frame

Answer 4

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

Question 5

Enumeration units

Answer 5

Units that contain one or more elements and that are to be listed in a sampling frame.

Question 6

Sampling units

Answer 6

Units listed at each stage of a multistage sampling design.

Question 7

Sampling error

Answer 7

Any difference between the characteristics of a sample and the characteristics of a population.

Question 8

Target population

Answer 8

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

Question 9

Representative sample

Answer 9

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. In an unrepresentative sample, some characteristics are overrepresented or underrepresented.

Question 10

Random sampling

Answer 10

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

Question 11

Probability of selection

Answer 11

The likelihood that an element will be selected from the population for inclusion in the sample. In a census of all the elements of a population, the probability that any particular element will be selected is 1.0. If half the elements in the population are sampled on the basis of chance (say, by tossing a coin), the probability of selection for each element is one half, or.5. As the size of the sample as a proportion of the population decreases, so does the probability of selection.

Question 12

Systematic bias

Answer 12

Overrepresentation or underrepresentation of some population characteristics due to the method used to select the sample.

Question 13

Probability sampling methods

Answer 13

Sampling methods that rely on a random or chance selection method so that the probability of selection of population elements is known.

Question 14

Simple random sampling

Answer 14

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

Question 15

Random numbers table

Answer 15

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

Question 16

Random digit dialing

Answer 16

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

Question 17

Systematic random sampling

Answer 17

A sampling method in which sample elements are selected from a list or sequential files, with every nth element being selected after the first element is selected randomly with the first interval.

Question 18

Sampling interval

Answer 18

The number of cases from sampled case to another in a systematic random sample.

Question 19

Stratified random sampling

Answer 19

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

Question 20

Proportionate stratified sampling

Answer 20

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

Question 21

Disproportionate stratified sampling

Answer 21

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

Question 22

Cluster sampling

Answer 22

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.

Question 23

Cluster

Answer 23

A naturally occurring mixed aggregate of elements of the population.

Question 24

Nonprobability sampling methods

Answer 24

Sampling methods in which the probability of selection of population elements is unknown.

Question 25

Availability sampling

Answer 25

Sampling method in which elements are selected on the basis of convenience.

Question 26

Quota sampling

Answer 26

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.

Question 27

Purposive sampling

Answer 27

A sampling method in which elements are selected for a purpose, usually because of their unique position.

Question 28

Snowball sampling

Answer 28

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

Question 29

Sampling distribution

Answer 29

The hypothetical distribution of a statistic across all the random samples that could be drawn from a population.

Question 30

Inferential statistics

Answer 30

Mathematical tools 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.

Question 31

Sample statistic

Answer 31

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

Question 32

Population parameter

Answer 32

The value of a statistic, such as a mean, computed using the data for the entire population.