Module 1: Gathering Data

These flashcards cover key concepts about data gathering methodologies and biases affecting research.

Census

A special sample that includes everyone; it 'samples' the entire population.

Sample Statistics

Summaries found from data in a sample, used as estimations for a population parameter.

Population Inference

When results from a sample can be generalized to an entire population as estimates.

Causal Inference

Inferences made when comparing results from treatment groups, indicating that differences are caused by treatment.

Random Sampling

Selecting individuals randomly from a population to eliminate the effect of unknown factors.

Sampling Variability

Differences in values for variables measured across different samples.

Stratified Random Sampling

Dividing the population into homogeneous groups (strata) and taking an SRS from each stratum.

Systematic Random Sampling

Sampling method where a starting individual is randomly selected, then every k-th person is chosen.

Cluster Sampling

Splitting the population into similar groups (clusters), randomly selecting a cluster, and conducting a census within it.

Selection Bias

Bias that occurs when some portion of the population is not sampled or has smaller representation than in the population.

Response Bias

Bias occurring due to factors in the survey design that influence responses.

Voluntary Response Bias

When individuals choose to participate in the survey, leading to biased results.

Nonresponse Bias

A bias that occurs when a large proportion of those sampled fail to respond.

Observational Study

A study where the investigator observes individuals and measures variables of interest without influencing responses.

Randomized Experiment

A study design that manipulates factor levels, randomly assigns subjects to treatment levels, and compares responses.

Lurking Variables

Variables that are not accounted for but could explain differences in response.

Prospective Study

A study that follows subjects over time to observe outcomes.

Retrospective Study

A study that looks back at existing data to find relationships.