Introduction to Biostatistics & Levels of Measurement

Flashcards covering key terms and definitions from the lecture notes on biostatistics and levels of measurement.

Statistics

The science of collecting, organizing, summarizing, analyzing, presenting, interpreting, and drawing conclusions from data.

Data

A set of values of one or more variables recorded on one or more observational units.

Datum

A single observation or value.

Primary data

Data collected directly by observation, questionnaires, record forms, interviews, or surveys.

Secondary data

Data obtained from existing sources such as census, medical records, or registries.

Dataset

Data for a set of variables collected in a group of persons.

Data table

A dataset organized into a table with one column for each variable and one row for each person.

Variable

A data collection unit whose value can vary.

Levels of measurement

Nominal, ordinal, interval, and ratio scales used to measure data.

Nominal data

Categorical data with unordered categories; categories must be mutually exclusive and exhaustive; data are labels.

Ordinal data

Categorical data with categories that can be ranked; distances between categories are not necessarily meaningful.

Interval data

Quantitative data with ordered values and equal intervals, but zero is arbitrary.

Ratio data

Quantitative data with meaningful zero; supports ratio comparisons (e.g., height, weight, income).

Binary data

Nominal data with only two categories (e.g., yes/no; smoker/non-smoker).

Discrete data

Quantitative data that take only certain values (counts); there are gaps between values.

Continuous data

Quantitative data that can take any value within a range (measured values).

Qualitative data

Non-numerical data; categorical in nature.

Quantitative data

Numerical data that can be measured and analyzed numerically.

Categorical data

Data grouped into categories based on qualitative traits; labels or names.

Data sources

Routinely kept records, surveys (census), experiments, and external sources.

Observational unit

The entity on which data are collected.

Hierarchical order of data scales

Nominal < Ordinal < Interval < Ratio.

Why data type matters

The type of data determines appropriate statistical analysis techniques.