Data Collection Basics and Sampling Methods Vocabulary

Comprehensive vocabulary flashcards covering basic statistical terms, data classification, sampling methods, sources of bias, and experimental design based on the lecture material.

Population

The group that collected data in a study is intended to describe.

Target Population

The intended population of a study, so named because a poorly designed study may collect data that is not actually representative of it.

Parameter

A value (average, percentage, etc.) calculated using all the data from a population.

Census

A survey of an entire population.

Sample

A smaller subset of the entire population, ideally one that is fairly representative of the whole population.

Statistic

A value (average, percentage, etc.) calculated using the data from a sample.

Categorical (Qualitative) Data

Pieces of information that allow us to classify the objects under investigation into various categories.

Quantitative Data

Responses that are numerical in nature and with which we can perform meaningful arithmetic calculations.

Sampling Bias

A condition where a sampling method does not give every member of the population an equal likelihood of being selected for the sample.

Simple Random Sample

A sample in which every member of the population and any group of members has an equal probability of being chosen.

Sampling Variability

The natural variation among samples, which is expected and unavoidable in random sampling.

Stratified Sampling

A sampling method in which a population is divided into subgroups (strata) and random samples are taken from each subgroup with sample sizes proportional to the subgroup's size in the population.

Quota Sampling

A variation on stratified sampling wherein samples are collected in each subgroup until the desired quota is met.

Cluster Sampling

A sampling method in which the population is divided into subgroups (clusters), and a set of entire subgroups are selected to be in the sample.

Systematic Sampling

A sampling method in which every $n^{\text{th}}$ member of the population is selected to be in the sample.

Convenience Sampling

The practice of choosing samples by selecting whoever is convenient.

Voluntary Response Sampling

A sampling practice where participants are allowed to volunteer to be part of the sample.

Voluntary Response Bias

The sampling bias that often occurs when data is collected only from individuals who volunteer to participate.

Self-Interest Study

Bias that can occur when the researchers conducting the study have a personal or financial interest in the outcome.

Response Bias

Bias that occurs when a responder gives inaccurate responses for any reason.

Perceived Lack of Anonymity

Bias occurring when a responder fears that giving an honest answer might negatively affect them.

Loaded Questions

Questions whose wording sways or influences participant responses.

Non-Response Bias

Bias introduced when individuals refusing to participate in a study influence the validity of the outcome.

Observational Study

A study based strictly on observations or measurements without applying a treatment.

Experiment

A study in which the effects of an applied treatment are measured.

Confounding

A situation in an experiment where it is not clear which factor caused the observed effect because multiple variables could have produced the result.

Control Group

A group of participants in an experiment that does not receive the treatment being tested, serving as a baseline.

Placebo Effect

The phenomenon where the effectiveness of a treatment is influenced by the patient's perception of how effective they expect it to be.

Placebo

A dummy treatment given to control for the placebo effect.

Placebo Controlled Experiment

An experiment that provides the control group with a placebo.

Blind Study

A study in which the participant does not know whether they are receiving the active treatment or a placebo.

Double-Blind Study

A study in which neither the participants nor those interacting with them know who is assigned to the treatment group or the control group.