Chapter 9: Examining Populations And Samples In Research

Question 1

Is a particular group of individuals or elements to be studied

Answer 1

Population

Question 2

the individual units of population(defines the selected group of people or elements)

Answer 2

Sample

Question 3

an entire set of individuals or elements who meet the sampling criteria

Example: adult males, 18 years of age or older, diagnosed with type 2 diabetes, and hospitalized with a lower extremity infection

Answer 3

Target population

Question 4

the portion of the target population to which the researcher has reasonable access (might include individuals within a state, city, hospital, or nursing units)

Example: Patients with diabetes who are in an acute care hospital in Dallas, TX

Answer 4

Accessible populations

Question 5

election of subset of a population to represent the whole population
(Defines the selection process)

Answer 5

Sampling

Question 6

characteristics that the subject or element must possess to be part of the target population

Example: adults 60 years of age or older, ability to speak and read English, and undergoing surgical replacement of one knee joint

Answer 6

Inclusion criteria

Question 7

characteristics that can cause a person or element to be excluded from the target population

Example: any study participant with a history of previous joint knee replacement surgery, diagnosis of dementia, and diagnosed with a debilitating chronic muscle disease were excluded from the preoperative teaching study

Answer 7

Exclusion criteria

Question 8

Means that the sample, accessible population, and target population are alike in as many ways as possible
-in terms of characteristics such as age, gender, ethnicity, income, and education, which often influence study variables

Answer 8

Representativeness

Question 9

extending the findings from the sample under study to the larger population. Extent is influenced by quality of study and consistency of the study’s findings.

Example: the findings from the study of male patients, diagnosed with type 2 diabetes, and hospitalized with an infection in Dallas, may be generalized to the target population of males with type 2 diabetes hospitalized in Texas urban hospitals or, more broadly, to urban hospitals in the southern United States. With this information, you can decide whether it is appropriate to use this evidence in caring for the same type of patients in your practice, with the goal of moving toward evidence-based practice

Answer 9

Generalization

Question 10

number of participants ,events, behaviors, or situations, examined in a study.

Answer 10

Sample size

Question 11

blueprint for conducting a study; maximizes control over factors that could interfere with the validity of findings and guides the planning and implementation of a study in a way that is most likely to achieve the intended goal

Answer 11

Research design

Question 12

random = equal chance (each person or element in a population has an opportunity to be selected for a sample

Answer 12

• Probability Sampling (Generalizability ↑)

Question 13

what are the types of probability sampling?

Answer 13

• simple random
• cluster random
• stratified random
• systemic random

Question 14

most basic of the probability sampling plans and is achieved by randomly selecting elements from the sampling frame (computerized).

Answer 14

Simple Random

Question 15

used in situations in which the researcher knows some of the variables in the population that are critical for achieving representativeness

Example, using race and ethnicity for __________, the researcher may define four strata: white non-Hispanic, black non-Hispanic, Hispanic, and other. The population may be 60% white non-Hispanic, 20% black non-Hispanic, 15% Hispanic, and 5% other. Researchers may select a random sample for each stratum equivalent to the target population proportions of that stratum.

Answer 15

Stratified; stratification

Question 16

a researcher develops a sampling frame that includes a list of all the states, cities, institutions, or clinicians with which elements of the identified population can be linked

Example: the researcher may first randomly select states and then randomly select cities within the sampled states. Next, the researcher may randomly select hospitals within the randomly selected cities. At this level, all patients on the nursing unit who fit the criteria for the study may be included or patients can be randomly selected

Answer 16

Cluster sampling

Question 17

is used when an ordered list of all members of the population is available. The process involves selecting every kth individual on the list, using a starting point selected randomly.

Example: if the population size is N = 1200 and the desired sample size is n = 100, then k = 12. Thus, the researcher would include every 12th person on the list in the sample

Answer 17

Systemic random

Question 18

Non-randor, not every element of a population has an opportunity to be selected for a study sample

Answer 18

Non-probability Sampling (Generalizability ↓)

Question 19

Types of non-probability sampling

Answer 19

• convenience
• purposeful
• theoretical
• network
• quota

Question 20

also called accidental sampling, is a relatively weak approach because it provides little opportunity to control for biases; participants are included in the study merely because they happen to be in the right place at the right time

ex: A classroom of students, patients attending a specific clinic, individuals in a support group, and patients hospitalized with a particular medical diagnosis are examples of ——— samples.

Answer 20

Convenience sampling

Question 21

uses a convenience sampling technique with an added feature—a strategy to ensure the inclusion of participant types likely to be underrepresented in the convenience sample, such as females, minority groups, older adults, and the poor, rich, and undereducated.

Answer 21

Quota sampling

Question 22

Judgmental or selective sampling, the researcher consciously selects certain participants, elements, events, or incidents, to include in the study

Example, researchers describing grief following the loss of a child might include parents who lost a child in the previous 6, 12, and 24 months, and the children who were lost might be of varying ages (< 5, 5 − 10, and > 10 years old). Ultimate goal of _______ sampling is selecting information-rich cases from which researchers can obtain in-depth information for their studies.

Answer 22

Purposeful sampling

Question 23

Or snowball sampling, chain, or nominated sampling, hold promise for locating participants who would be difficult or impossible to obtain in other ways or who had not been previously identified

Ex: if a study were being conducted to describe the lives of adolescents who are abusing substances, ——- sampling would enable researchers to find participants who have a prolonged history of substance abuse and who could provide rich information about their lives in an interview.

Answer 23

Network sampling

Question 24

is used in qualitative research to develop a selected theory or model through the research process.researcher gathers data from any person or group who can provide relevant, varied, and rich information for theory generation.

The data are considered relevant and rich if they include information that generates, delimits, and saturates the theoretical codes in the study needed for theory generation

Answer 24

Theoretical sampling

Question 25

In quantitative studies what are factors that influence the adequacy of sample size:

Answer 25

Effect Size
types of quantitative studies
number of variables
measurement sensitivity
data analysis techniques

**uses power analysis

Question 26

In Qualitative studies what are important factors that need to be considered in determining sample size:

Answer 26

Scope of the study
nature of the topic
quality of the data
study design

*uses data saturation

Question 27

the size of difference between the groups or the strength of the relationship between two variables.

Answer 27

Effect size

Question 28

Small effect size

Answer 28

<0.30 or < -0.30

Question 29

Medium effect size

Answer 29

= 0.30 to 0.50 or -0.30 to - 0.50

Question 30

Large effect size

Answer 30

> 0.50 or >-.50

Question 31

What are the types of settings?

Answer 31

Natural setting
partially controlled
highly controlled

Question 32

uncontrolled, real-life situation environment

researcher does not manipulate or change the environment for the study

Answer 32

Natural or field setting

Question 33

is an environment that is manipulated or modified in some way by the researcher

Ex, private conference room in clinic, but in non business hours to reduce noise

Answer 33

Partially controlled setting

Question 34

is an environment structured for the purpose of conducting research

Ex. Laboratories research or experimental centers, and test units in hospitals or facilities

Answer 34

Highly controlled setting

Question 35

__________is an effective way to determine an adequate sample size for quantitative and outcomes studies.

In __________, effect size, level of significance (a = 0.05), and standard port(0.8 or 80%) are used to determine sample size for a prospective study and evaluate the sample size of a complete study

Answer 35

Power analysis; power analysis

Question 36

Individual units of the population and sample

*participants

Answer 36

Elements