Chapter 12 Pwpt

Question 1

What is sampling?

Answer 1

Process of selecting representative units (subjects) of a population

Question 2

Description of sampling strategy is usually found in the _______ _________.

Answer 2

Methods section

Question 3

___________ and ___________ __________ must be described by the researcher

Answer 3

Exclusion and inclusion criteria

Question 4

What is important to consider about sampling?

Answer 4

How does the sampling strategy limit the potential effect of extraneous variables or bias to explain the results of the study?

Question 5

A sample should be _______________ because it has ______________________________.

Answer 5

Representative; the same key characteristics as the entire population

Question 6

What is the purpose of sampling?

Answer 6

To be more efficient; it is non cost effective, or even feasible to study the whole population

Question 7

Two types of sampling are _______ or ________ and _________ or _________.

Answer 7

Nonprobablility or purposive sampling

Probability or random sampling

Question 8

Non probability (purposive) sampling is where?

Answer 8

Inclusion in study sample is NOT random
Less generalizable
Less representative

Question 9

Types of nonprobability (purposive) sampling are?

Answer 9

Convenience
Quota
Matching
Networking sampling (snowball sampling)

Question 10

Probability (random) sampling does what?

Answer 10

Uses randomization to include include in sample
More generalizable
More representative

Question 11

Types of probability (random) sampling are?

Answer 11

Simple random sampling
Stratified random sampling
Cluster sampling

Question 12

Remember that random sampling DOES NOT equal

Answer 12

Random assignment to group

Question 13

Sampling threats of internal validity

Answer 13

Selection effect - bias in selecting

Attrition and mortality- loss of subjects

Question 14

Sampling threats of external validity

Answer 14

Generalizability to other populations or settings

Question 15

Critical appraisal of nonprobability samples

Answer 15

What motivated some of the people to participate and others not to participate (self-selection)?
What kind of data would have been obtained if nonparticipants had also responded?
How representative are the people who did participate in relation to the population of interest?
What kind of confidence can you have in the evidence provided by the findings, based on the sampling strategy?

Question 16

Sample size must consider?

Answer 16

Type of design and sample procedure
Formula used for estimating sample size (power analysis)
Heterogeneity of attributes investigated
How often the phenomenon occurs in the population
Projected cost

Question 17

The power analysis is used to determine the…?

Answer 17

Number for each group of a study

Question 18

To perform a power analysis, what needs to be determined?

Answer 18

Effect size, level of significance, how much power of detection is desired

Question 19

As we increase power to avoid a ___________, we get an increased chance of making a __________.

Answer 19

Type 1 error; type 2 error

Question 20

How much power of detection is desired? Set to avoid a type 2 error. What is a type 2 error?

Answer 20

When the results are not statistically significant, when there is a real relationship between variables or a difference between groups

Question 21

Level of significance: set by the researcher to avoid a type 1 error. What is a type one error?

Answer 21

When the statistical analysis determines that there is a difference between groups or correlation between variables when there is not.

Question 22

When might an entire population most likely be used in a research study?

Answer 22

When the population size is very small

Question 23

What type of sampling includes using the internet and social networking to locate samples that are otherwise difficult or impossible to locate?

Answer 23

Snowball sampling