Research Variables

Applied statistics for medical and biologic problems

What is biostatistics?

Value stays the same from person to person or over time

What is a constant?

Value or categories cannot be predicted with certainty

What is a variable?

Qualitative, categorical data without measurement units

What is a nominal variable?

Data ranked or ordered, qualitative or quantitative

What is an ordinal variable?

Countable integers with finite values, cannot be subdivided meaningfully

What is a discrete variable?

Quantitative data with any value over a range, including fractions

What is a continuous variable?

Variable manipulated or categorized to observe effect

What is an independent variable?

Variable affected or measured as outcome

What is a dependent variable?

Variable that distorts estimated effect, is risk factor, associated with exposure, not caused by disease

What is a confounder?

Specifies how variables are measured or categorized

What are operational definitions?

Descriptive, non-numeric variables

What are qualitative variables?

Numeric measurement variables

What are quantitative variables?