covariance: meaning, definition, pronunciation and examples
C1/C2Highly technical/academic, primarily scientific.
Quick answer
What does “covariance” mean?
A measure of how much two random variables change together.
Audio
Pronunciation
Definition
Meaning and Definition
A measure of how much two random variables change together.
In statistics, it quantifies the joint variability of two variables; a positive covariance indicates that the variables tend to move in the same direction, while a negative covariance indicates they move inversely. In broader contexts, it can refer to a concurrent or correlated change between two entities.
Dialectal Variation
British vs American Usage
Differences
No significant linguistic difference in usage. Spelling is consistent (no 'z').
Connotations
None beyond the technical meaning.
Frequency
Equally low-frequency and specialised in both dialects.
Grammar
How to Use “covariance” in a Sentence
the covariance between X and Ythe covariance of X and Ya covariance of [number]Vocabulary
Collocations
Examples
Examples of “covariance” in a Sentence
adjective
British English
- The covariance matrix is crucial for the analysis.
- They studied the covariance structure of the data.
American English
- The covariance estimate was reported in the appendix.
- A covariance analysis was performed.
Usage
Meaning in Context
Business
Used in finance and econometrics to describe how asset returns move together in a portfolio.
Academic
Core concept in statistics, probability theory, machine learning, and quantitative social sciences.
Everyday
Extremely rare; only used in explaining statistical concepts.
Technical
The primary domain of use; essential for data analysis, signal processing, and scientific modelling.
Vocabulary
Synonyms of “covariance”
Neutral
Weak
Vocabulary
Antonyms of “covariance”
Watch out
Common Mistakes When Using “covariance”
- Using 'covariance' to mean 'correlation' (correlation is a standardised form of covariance).
- Pronouncing it as /ˈkəʊ.vɛər.əns/ (incorrect stress on first syllable).
- Treating it as a general synonym for 'relationship'.
FAQ
Frequently Asked Questions
Covariance measures the direction of the linear relationship (positive or negative) and is scale-dependent. Correlation (specifically Pearson's) standardises this measure to a range between -1 and +1, indicating both direction and strength independently of scale.
Not directly, because its magnitude depends on the units of measurement. For comparability, you should use the correlation coefficient, which is dimensionless.
Not necessarily. A high numerical value can be driven by large variances in the individual variables, not necessarily a strong linear relationship. Always consider the context and the scale of the data.
It is fundamental in statistics, finance (portfolio theory), machine learning (e.g., for Principal Component Analysis), genetics (quantitative trait analysis), and any field involving multivariate data analysis.
A measure of how much two random variables change together.
Covariance is usually highly technical/academic, primarily scientific. in register.
Covariance: in British English it is pronounced /kəʊˈveər.i.əns/, and in American English it is pronounced /koʊˈver.i.əns/. Tap the audio buttons above to hear it.
Learning
Memory Aids
Mnemonic
Think of 'co-' (together) and 'variance' (variation) → how two things vary together.
Conceptual Metaphor
A DANCE PARTNERSHIP: If they move in sync (positive covariance), they are coordinated. If one moves forward when the other moves back (negative covariance), they are in opposition.
Practice
Quiz
What does a negative sample covariance indicate?