Glossary of Terms

All complex subjects have their own terminology that sometimes makes it hard for new people to break into the field. This sometimes includes uncommon words, but more often than not a subject will have very specific meanings for common words - the discussion of errors vs mistakes in this video is a good example of this.

This glossary is a reference of some of the uncommon terms and specific definitions of more common words that you will encounter throughout Data Tree and your broader dealings with data. 

Many of these definitions come from the course materials and experts that helped develop Data Tree. Others come from the CASRAI Dictionary. Those definitions are kindly made available under a Creative Commons Attribution 4.0 International License.

Browse the glossary using this index

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Inference is the process of deducing properties of the underlying distribution or population, by analysis of data. It is the process of making generalizations from the sample to a population.


The science of collecting, classifying, storing, retrieving and disseminating data and/or knowledge.


The aggregation of data to make coherent observations about the world, meaningful data, or data arranged or interpreted in a way to provide meaning.

- CASRAI Dictionary

It is often considered the job of the scientist, researcher or statistician to derive information from raw data.


In the electromagnetic spectrum, the visible light region lies from violet at shorter wavelengths/energies to red at longer wavelengths/energies. Infrared radiation has wavelengths just greater than red light and emitted particularly by heated objects. For example, night vision goggles use infrared radiation.


A number which is not a fraction; a whole number.

Inter-quartile range

The interquartile range is the difference between the upper and lower quartiles. If the lower and upper quartiles are denoted by Q1 and Q3, respectively, the interquartile range is (Q3 - Q1). The phrase ‘interquartile range’ was first used by Galton in 1882.

Internet of Things

Abbreviated to IoT, a broad term for devices interconnected via the internet enabling sending and receiving of data or instructions. These devices include everyday items such as home appliances or cameras. Sometimes also referred to as ‘smart devices'.


The capability to communicate, execute programs, or transfer data among various functional units in a useful and meaningful manner that requires the user to have little or no knowledge of the unique characteristics of those units. Foundational, syntactic, and semantic interoperability are the three necessary aspects of interoperability.

- CASRAI Dictionary