Week 8: Quantitative Research Survey

These flashcards cover key concepts related to sampling design and sample size determination for surveys.

Sampling

A process of selecting a sample of appropriate characteristics and adequate size to estimate population parameters.

Sample

subset of the population

Population

The entire group or collection of individuals or items of interest in the study.

Target Population

The population to which one would like to generalize the results of the study.

Study Population

The population actually studied where the sample was obtained.

Probability Sampling

Every element of the population has a known chance of being selected.

Non-Probability Sampling

Elements are chosen without regard to the chance of being selected.

Sample Size Calculation

The process of determining the number of subjects required for a study to ensure adequate power and validity.

Confidence Level

The degree of confidence that one wants in stating that the estimate is within a specified tolerable error.

Simple Random Sampling

A sampling design where any collection of n elementary units from the population is a possible sample and each has the same chance of being selected.

Systematic sampling

sampling design wherein every kth element of the population is chosen

Stratified Random Sampling

A sampling design where the population is divided into non-overlapping groups called strata, and sampling is done within each stratum.

Cluster Sampling

A sampling design where the population is first divided into sampling units, then units are selected, and every element found in each selected group is included in the sample

Multi-stage Cluster Sampling

A sampling design that involves selecting samples in stages (from primary to secondary, etc), progressively narrowing down the population.

Cohort studies

no sampling involved in the special cohorts; may sample from a bigger comparison group (for studies with comparison group)

Case-control studies

No sampling of case but controls are sampled (neighborhood, hospital-based)

Cross-sectional

For testing of associations, estimation of population parameters

Quota Sampling

Obtains samples of a fixed size from pre-determined subdivisions of the population.

Judgmental Sampling

A representative sample selection based on an expert’s subjective judgment.

Accidental or haphazard sampling

sample is made up of those who come at hand or who is available. (e.g. ambush interviews)

Snowball Technique

sample is obtained by a process whereby an individual to be included is identified by a member who was previously included

Sampling Frame

A list or database used to define the population from which a sample is drawn.

Significance Level

The probability of rejecting the null hypothesis when it is true.

Variability of Measurement

A measure of variation and inconsistency within data.

Drop Outs

Subjects who discontinue participation in a study, which necessitates increasing sample size to account for their absence.