interquartile range
LowTechnical/Academic
Definition
Meaning
A measure of statistical dispersion, representing the range of the middle 50% of a dataset.
In descriptive statistics, it is calculated as the difference between the third quartile (Q3) and the first quartile (Q1). It is resistant to outliers and is often used to identify variability and potential anomalies in data.
Linguistics
Semantic Notes
This is a single, fixed statistical term; it cannot be meaningfully separated (e.g., 'interquartile' is not used independently).
Dialectal Variation
British vs American Usage
Differences
No significant differences in definition or usage. Spelling conventions follow general norms (e.g., 'analyse' vs. 'analyze' in surrounding text).
Connotations
Purely technical and neutral in both variants.
Frequency
Equally low frequency and confined to statistical contexts in both regions.
Vocabulary
Collocations
Grammar
Valency Patterns
The interquartile range of [dataset] is [value].[Dataset] has an interquartile range of [value].Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “No common idioms use this term.”
Usage
Context Usage
Business
Used in data analysis reports, market research, and performance metrics to summarize variability.
Academic
Core term in statistics, psychology, and sciences for describing data spread.
Everyday
Virtually never used in casual conversation.
Technical
The primary and exclusive context of use.
Examples
By Part of Speech
verb
British English
- We need to interquartile the data. (INCORRECT - not used as a verb)
American English
- You cannot interquartile range the numbers. (INCORRECT - not used as a verb)
adverb
British English
- The data was spread interquartilely. (INCORRECT - not used as an adverb)
American English
- They analyzed the results interquartile. (INCORRECT - not used as an adverb)
adjective
British English
- The interquartile-range calculation is key. (Hyphenated compound adjective)
American English
- An interquartile range value was reported. (Noun phrase used attributively)
Examples
By CEFR Level
- (Not applicable for A2 level.)
- The teacher showed us how to find the interquartile range on a box plot.
- A smaller interquartile range indicates that the data points are clustered more tightly around the median.
- Outliers were defined as observations falling more than 1.5 times the interquartile range above the third quartile or below the first quartile.
Learning
Memory Aids
Mnemonic
Imagine a box (the middle 50% of data) inside the full range of a dataset. The InterQuartile Range is simply the length of that box.
Conceptual Metaphor
DATA SPREAD AS PHYSICAL SPACE (The 'range' is a 'distance' between two points (Q1 and Q3) within the data landscape).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid a word-for-word translation like 'межквартальный диапазон.' The standard term is 'интерквартильный размах' or 'межквартильный размах.'
Common Mistakes
- Confusing it with the full range (max-min).
- Using 'interquartile' as an independent adjective.
- Misspelling as 'interquantile range.'
Practice
Quiz
What does the interquartile range (IQR) measure?
FAQ
Frequently Asked Questions
It is calculated by subtracting the first quartile (Q1, the 25th percentile) from the third quartile (Q3, the 75th percentile). IQR = Q3 - Q1.
The IQR is not affected by extreme values (outliers) at the very high or low ends of the dataset, making it a more robust measure of spread than the full range.
In a box plot, the length of the central box (the rectangle) visually represents the interquartile range.
Yes, if Q3 equals Q1, the IQR is zero. This indicates that the middle 50% of the data consists of identical values, suggesting no variability in that portion.