Sampling in quantitative research презентация

Question Tell whether the following statement is true or false: The aggregate of cases in which a researcher is interested is called a sample.

Answer False The 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.

Basic Sampling Concepts in Quantitative Studies Population: the aggregate of cases in which a researcher 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

Eligibility Criteria Establish population characteristics Determine participation in study Maximize construct validity Inclusion Exclusion

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

Answer False Researchers usually sample from the accessible population but should identify the target population to which they want to generalize their results.

Basic Sampling Concepts in Quantitative Studies Representative sample A 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

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

Answer True Probability sampling involves random selection of elements.

Basic Sampling Concepts in Quantitative Studies (cont.) Probability sampling Involves random selection of elements   Nonprobability sampling Does not involve selection of elements at random

Nonprobability Sampling Convenience sampling Snowball sampling Quota sampling Consecutive sampling Purposive sampling

Probability Sampling Simple random sampling Stratified random sampling Multistage sampling Cluster sampling Systematic sampling

Power Analysis Estimate sample size Large samples preferred to small samples