Section1.3

Simple Random Sample

A sample of n subjects selected so that every possible sample of the same size n has the same chance of being chosen.

Observational Study

A study that observes and measures specific characteristics without attempting to modify the individuals being studied.

Experiment

A process where a treatment is applied to observe its effects on the individuals, known as experimental units or subjects.

Placebo

A harmless and ineffective treatment used for comparison in experiments.

Blinding

A technique where the subject does not know whether they are receiving a treatment or a placebo.

Randomization

The process of assigning subjects to different groups through random selection to create similar groups.

Cross-sectional study

A study where data are observed, measured, and collected at a single point in time.

Retrospective study

A study that collects data from a past time period by examining records or conducting interviews.

Confounding

Occurs when an observed effect can't be attributed to any specific factor due to overlapping influences.

Sampling error

The error that occurs due to the discrepancy between a sample result and the true population result.