Chapter 10

Question 1

The aggregate of cases in which a researcher is interested

Answer 1

Population

Question 2

Selection of a portion of the population (a sample) to represent the entire population

Answer 2

Sampling

Question 3

Subpopulations of a population (e.g., male/female)

Answer 3

Strata

Question 4

The entire population of interest

Answer 4

Target Population

Question 5

The portion of the target population that is accessible to the researcher, from which a sample is drawn.

Answer 5

Accessible population

Question 6

A sample whose key characteristics closely approximate those of the target population—a sampling goal in quantitative research.

Answer 6

Representative sample

Question 7

HOw is representative sampling achieved?

Answer 7

Probability sampling
Homogeneous populations
Larger samples

Question 8

The systematic over- or under-representation of segments of the population on key variables when the sample is not representative.

Answer 8

Sampling bias

Question 9

Differences between sample values and population values.

Answer 9

Sampling error

Question 10

Involves random selection of elements: each element has an equal, independent chance of being selected

Answer 10

Probability sampling

Question 11

Does not involve selection of elements at random

Answer 11

Non-probability sample

Question 12

Examples of non-probability sampling

Answer 12

Convenience sampling
Snowball (network) sampling
Quota sampling
Purposive sampling

Question 13

Use of the most conveniently available people
Most widely used approach by quantitative researchers
Most vulnerable to sampling biases

Answer 13

Convenience Sampling

Question 14

Referrals from other people already in a sample
Used to identify people with distinctive characteristics
Used by both quantitative and qualitative researchers; more common in qualitative.

Answer 14

Snowball Sampling

Question 15

Convenience sampling within specified strata of the population.
Enhances representativeness of sample.
Infrequently used, despite being a fairly easy method of enhancing representativeness.

Answer 15

Quota Sampling

Question 16

Involves taking all of the people from an accessible population who meet the eligibility criteria over a specific time interval, or for a specified sample size
A strong nonprobability approach for “rolling enrollment” type accessible populations
Risk of bias low unless there are seasonal or temporal fluctuations

Answer 16

Consecutive Sampling

Question 17

Sample members are hand-picked by researcher to achieve certain goals.
Used more often by qualitative than quantitative researchers.
Can be used in quantitative studies to select experts or to achieve other goals.

Answer 17

Purposive

Question 18

Types of Probability Sampling

Answer 18

Simple random sampling
Stratified random sampling
Cluster (multistage) sampling
Systematic sampling

Question 19

Uses a sampling frame – a list of all population elements
Involves random selection of elements from the sampling frame
Not to be confused with random assignment to groups in experiments!
Cumbersome; not used in large, national surveys

Answer 19

Simple Random Sampling

Question 20

Population is first divided into strata, then random selection is done from the stratified sampling frames
Enhances representativeness
Can sample proportionately or disproportionately from the strata

Answer 20

Stratified Random Sampling

Question 21

Successive random sampling of units from larger to smaller units (e.g., states, then zip codes, then households)
Widely used in national surveys
Larger sampling error than in simple random sampling, but more efficient

Answer 21

Cluster Sampling

Question 22

Sample Size Qualifications

Answer 22

The number of study participants in the final sample.
Sample size adequacy is a key determinant of sample quality in quantitative research.
Sample size needs can and should be estimated through power analysis for studies seeking causal inference.

Question 23

Examples of Records, Documents, and Available Data

Answer 23

Hospital records (e.g., nurses’ shift reports)
School records (e.g., student absenteeism)
Corporate records (e.g., health insurance choices)
Letters, diaries, minutes of meetings, etc.
Photographs

Question 24

Major Types of Data Collection Methods

Answer 24

Self-report

Observation

Biophysiologic measures

Question 25

Advantages of Questionnaires

Answer 25

Lower costs
Possibility of anonymity, greater privacy
Lack of interviewer bias

Question 26

Advantages of Interviews

Answer 26

Higher response rates
Appropriate for more diverse audiences
Opportunities to clarify questions or to determine comprehension
Opportunity to collect supplementary data through observation

Question 27

used to make fine quantitative discriminations among people with different attitudes, perceptions, traits

Answer 27

Scales

Question 28

Likert Scales

Answer 28

Consist of several declarative statements (items) expressing viewpoints
Responses are on an agree/disagree continuum (usually 5 or 7 response options).
Responses to items are summed to compute a total scale score.

Question 29

Semantic Differential Scales

Answer 29

Require ratings of various concepts.
Rating scales involve bipolar adjective pairs, with 7-point ratings.
Ratings for each dimension are summed to compute a total score for each concept.

Question 30

Visual Analog Scale (VAS)

Answer 30

Used to measure subjective experiences (e.g., pain, nausea) – see a lot in peds
Measurements are on a straight line measuring 100 mm
End points labeled as extreme limits of sensation

Question 31

Response Set Biases

Answer 31

Biases reflecting the tendency of some people to respond to items in characteristic ways, independently of item content

Question 32

Response Set Bias Examples

Answer 32

Social desirability response set bias
Extreme response set
Acquiescence response set (yea-sayers)
Nay-sayers response set

Question 33

Evaluation of Self-Reports

Answer 33

Strong on directness
Allows access to information otherwise not available to researchers
But can we be sure participants actually feel or act the way they say they do?

Question 34

phenomena Amenable to Research Observation

Answer 34

Activities and behavior
Characteristics and conditions of individuals 
Skill attainment and performance
Verbal and nonverbal communication
Environmental characteristics