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# Sampling in quantitative research

## 1.

Chapter 12Sampling in Quantitative

Research

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins

## 2. Question

Tell whether the following statement is true or false:The aggregate of cases in which a researcher is

interested is called a sample.

Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins

## 3. Answer

FalseThe aggregate of cases in which a researcher is

interested is called a population. A sample is

selection of a portion of the population to represent

the entire population.

Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins

## 4. Basic Sampling Concepts in Quantitative Studies

Population: the aggregate of cases in which aresearcher is interested

Sampling: selection of a portion of the population (a

sample) to represent the entire population

Element: basic population unit about which

information is collected

Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins

## 5. Eligibility Criteria

• Establish population characteristics• Determine participation in study

• Maximize construct validity

• Inclusion

• Exclusion

Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins

## 6. Question

Tell whether the following statement is true or false:Researchers usually sample from the target

population.

Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins

## 7. Answer

FalseResearchers usually sample from the accessible

population but should identify the target population

to which they want to generalize their results.

Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins

## 8. Basic Sampling Concepts in Quantitative Studies

Representative sampleA sample whose key characteristics closely

approximate those of the population

Sampling bias

The systematic over- or underrepresentation of

segments of the population on key variables

Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins

## 9. Question

Tell whether the following statement is true or false:Probability sampling involves random selection of

elements.

Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins

## 10. Answer

TrueProbability sampling involves random selection of

elements.

Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins

## 11. Basic Sampling Concepts in Quantitative Studies (cont.)

Probability samplingInvolves random selection of elements

Nonprobability sampling

Does not involve selection of elements at random

Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins

## 12. Nonprobability Sampling

• Convenience sampling• Snowball sampling

• Quota sampling

• Consecutive sampling

• Purposive sampling

Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins

## 13. Probability Sampling

• Simple random sampling• Stratified random sampling

• Multistage sampling

• Cluster sampling

• Systematic sampling

Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins

## 14. Power Analysis

• Estimate sample size• Large samples preferred to small samples

Copyright © 2017 Wolters Kluwer Health | Lippincott Williams & Wilkins