# Statistics notes - types of data

(Redirected from Nominal data)
 This is more for overview of my own than for teaching or exercise. Arithmetic · 'elementary mathematics' and similar concepts Set theory, Category theory Geometry and its relatives · Topology Elementary algebra - Linear algebra - Abstract algebra Calculus and analysis Logic Semi-sorted  : Information theory · Number theory · Decision theory, game theory · Recreational mathematics · Dynamical systems · Unsorted or hard to sort Math on data: Statistics as a field some introduction · areas of statistics types of data · on random variables, distributions Virtues and shortcomings of... on sampling · probability glossary · references, unsorted Footnotes on various analyses Other data analysis, data summarization, learning Statistical modeling · Classification, clustering, decisions · dimensionality reduction · Optimization theory, control theory Connectionism, neural nets · Evolutionary computing

 This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

## One possible typology

### Ratio data (ordered, meaningful zero point, linear scale, (often) continuous)

Examples:

• weight
• length
• time amount - reaction time, hours of study, time required to run a marathon
• age
• temperature in Kelvin
• number of responses (overlap with discrete numeric)

### Ordinal data (ordered, but no obvious numbering so not linear; discrete)

Examples:

• highest level of education
• questionnaire items of the disagree/disagree, happy/unhappy type
• socioeconomic status
• age groups ('age up to 20', 'age 20-29', 'age 30-39') (note: in this case based on ratio data)
• ranks

Asking people to rate on a few-point scale is often seen as ordinal, while there is overlap with continuous interval data.

### Nominal/categorical data (unordered; qualitative; discrete)

Examples:

• labels, such as {T,A,G,C}
• choosing from multiple choice options
• distinguishers such as {green,blue} or {true,false}, (discrete) gender, blood type
• brand names
• left/right-handedness
• political affiliation

## More words

### Further terms that matter

Continuous data refers to valued numbering that is not restricted to be discrete/integer.

so ratio or interval data in the above list.

Quantitative data - basically anything not categorical, so referring to nominal/categorical.