biostats quiz 1

Population

The entire group of interest.

Sample

A subset of the population.

Parameter

A numerical summary of a population.

Statistic

A numerical summary of a sample.

Qualitative Variable

A variable that describes characteristics or qualities and is not numerical.

Quantitative Variable

A variable that represents numerical values.

Discrete Variable

A quantitative variable with countable values (ex: number of siblings).

Continuous Variable

A quantitative variable with measured values (ex: height

Nominal Scale

Categories with no order (ex: hair color).

Ordinal Scale

Categories with an order

Interval Scale

Ordered scale with no true zero (ex: temperature in °F or °C).

Ratio Scale

Ordered scale with a true zero (ex: age

Observational Study

Data is collected by observing only; no cause-and-effect can be concluded.

Experiment

Treatments are applied; cause-and-effect relationships can be determined.

Simple Random Sample (SRS)

A sample where every individual has an equal chance of being selected.

Stratified Sampling

Population is divided into strata (groups) based on a characteristic; then random samples are taken from each group. Ensures representation of all groups.

Convenience Sampling

Sample is taken from individuals who are easily available; not random, may be biased.

Systematic Sampling

Select every kth individual from a population list after choosing a random starting point.