# Variance vs. Variability — What's the Difference?

Edited by Tayyaba Rehman — By Maham Liaqat — Updated on May 3, 2024

**Variance is statistical measure of the spread of numbers in dataset, computed as the average squared deviation from the mean; variability, on the other hand, is broader term describing the overall spread of data without specific mathematical formula.**

## Difference Between Variance and Variability

### Table of Contents

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## Key Differences

Variance specifically quantifies the spread of a dataset by averaging the squared differences from the mean. Whereas variability describes the extent to which these data points differ from each other in general, indicating the overall dispersion within a dataset.

In statistics, variance is calculated using a precise formula, which makes it a consistent and reliable measure for comparing the spread among different datasets. On the other hand, variability is a more qualitative concept that encompasses various ways to assess spread, such as range, interquartile range, and standard deviation.

Variance is typically used in statistical models and hypothesis testing to understand the data's behavior around the mean. Variability, however, is often discussed in more descriptive statistics to provide a basic understanding of the data's spread.

Variance can be misleading if outliers are present, as they heavily influence the mean and, consequently, the variance. In contrast, measures of variability like the range or median absolute deviation can provide a more robust picture of data spread in the presence of outliers.

Variance is always non-negative and has squared units of the original data, which can complicate its interpretation. In contrast, measures of variability can be in the same units as the data, making them more intuitive to understand.

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## Comparison Chart

### Definition

Statistical measure of data spread based on the mean.

General term describing data spread without precise formula.

### Calculation

Squared differences from the mean averaged.

Assessed through range, standard deviation, etc.

### Sensitivity to Outliers

High, as outliers influence the mean significantly.

Less, often uses medians or other non-mean measures.

### Units

Squared units of the data.

Same units as the data or unitless.

### Usage in Statistics

Used in formal statistical analyses and modeling.

Used descriptively to discuss data characteristics.

## Compare with Definitions

#### Variance

It is calculated as the average of the squared differences from the mean.

Variance considers each data point's contribution to overall spread.

#### Variability

Low variability implies data points are closely clustered.

Tightly grouped data points suggest low variability.

#### Variance

A zero variance implies that all values are identical.

All scores being equal in a test would result in zero variance.

#### Variability

Variability refers to how spread out or dispersed the data are.

High variability means data points are widely scattered.

#### Variance

Variance measures how far each number in the set is from the mean.

A higher variance indicates a wider spread of numbers.

#### Variability

It can be qualitatively described without mathematical computation.

Visual scatter plots can show variability through data dispersion.

#### Variance

Variance is used in determining the volatility of stock returns.

A stock with higher variance is considered riskier.

#### Variability

In statistical summaries, variability provides insights into data consistency.

Consistent manufacturing processes show low variability in product dimensions.

#### Variance

Variance can be decomposed into explained and unexplained parts in regression analysis.

Variance helps assess model fit by showing residual spread.

#### Variability

Variability can be assessed by range or interquartile range.

The range provides a quick sense of data spread.

#### Variance

In probability theory and statistics, variance is the expectation of the squared deviation of a random variable from its mean. Variance is a measure of dispersion, meaning it is a measure of how far a set of numbers is spread out from their average value.

#### Variability

Lack of consistency or fixed pattern; liability to vary or change

Seasonal variability in water levels

A great deal of variability in quality

Our results showed substantial variabilities in laboratory practices

#### Variance

The fact or quality of being different, divergent, or inconsistent

Her light tone was at variance with her sudden trembling

The stylistic variances of classical dance

#### Variability

The quality, state, or degree of being variable or changeable.

#### Variance

An official dispensation from a rule or regulation, typically a building regulation.

#### Variability

The state or characteristic of being variable.

#### Variance

The state or quality of being variant or variable; variation

Considerable variance in temperature across the region.

#### Variability

The degree to which a thing is variable. In data or statistics this is often a measurement of distance from the mean or a description of data range.

#### Variance

Difference or inconsistency

Your behavior is at variance with your beliefs.

#### Variability

The quality or state of being variable; variableness.

#### Variance

The state or fact of being in disagreement or in conflict

I am at variance with her over who should pay for the damage.

#### Variability

The power possessed by living organisms, both animal and vegetable, of adapting themselves to modifications or changes in their environment, thus possibly giving rise to ultimate variation of structure or function.

#### Variance

A discrepancy between two statements or documents, especially between the charge in a criminal indictment and the evidence presented.

#### Variability

The quality of being subject to variation

#### Variance

An exception to the application of a usual rule, granted by an authority on the basis of hardship or practicality

A zoning variance.

#### Variability

A quality of variability and lack of uniformity

#### Variance

(Statistics) The square of the standard deviation.

#### Variance

(Chemistry) The number of thermodynamic variables, such as temperature and pressure, required to specify a state of equilibrium of a system, given by the phase rule; the degrees of freedom of a system.

#### Variance

The act of varying or the state of being variable.

#### Variance

A difference between what is expected and what is observed; deviation.

#### Variance

The state of differing or being in conflict.

#### Variance

An official permit to do something that is ordinarily forbidden by regulations.

#### Variance

(law) A discrepancy between two legal documents.

#### Variance

(law) A departure from a cause of action originally in a complaint.

#### Variance

(statistics) The second central moment in probability.

#### Variance

The number of degrees of freedom in a system.

#### Variance

Covariance and contravariance generally.

Depending on the variance of the type constructor, the subtyping relation of the simple types may be either preserved, reversed, or ignored for the respective complex types.

#### Variance

The quality or state of being variant; change of condition; variation.

#### Variance

Difference that produces dispute or controversy; disagreement; dissension; discord; dispute; quarrel.

That which is the strength of their amity shall prove the immediate author of their variance.

#### Variance

A disagreement or difference between two parts of the same legal proceeding, which, to be effectual, ought to agree, - as between the writ and the declaration, or between the allegation and the proof.

#### Variance

The expected value of the square of the deviation from the mean of a randomly distributed variable; the second moment about the mean. This is also the square of the standard deviation.

#### Variance

An event that departs from expectations

#### Variance

Discord that splits a group

#### Variance

The second moment around the mean; the expected value of the square of the deviations of a random variable from its mean value

#### Variance

A difference between conflicting facts or claims or opinions;

A growing divergence of opinion

#### Variance

The quality of being subject to variation

#### Variance

An activity that varies from a norm or standard;

Any variation in his routine was immediately reported

## Common Curiosities

#### What does high variance indicate about a dataset?

High variance indicates a wide spread of data points around the mean, suggesting greater dispersion.

#### What is variability in statistics?

Variability refers to the overall spread of data points in a dataset, indicating how much the data varies.

#### How can variability be measured?

Variability can be measured using different statistics such as range, interquartile range, and standard deviation.

#### What are some common measures of variability?

Common measures include the range, variance, standard deviation, and interquartile range.

#### How is variance calculated?

Variance is calculated by averaging the squared differences from the mean of the dataset.

#### Why is variance important in statistics?

Variance is crucial for understanding data distribution and is fundamental in statistical hypothesis testing and regression analysis.

#### How does variability help in data analysis?

Variability provides insights into the spread and consistency of data, which helps in quality control and risk assessment.

#### What is variance?

Variance is a statistical measure that quantifies the dispersion of a dataset relative to its mean.

#### Can variability be negative?

Variability cannot be negative; it reflects the magnitude of dispersion and is always non-negative.

#### Is variance always relevant in statistical analysis?

Variance is relevant in many statistical analyses but may not be suitable in cases with highly skewed data or outliers.

#### Does variance have the same units as the original data?

No, variance has units that are the square of the original data units.

#### What impact do outliers have on variance?

Outliers can significantly increase variance because they affect the calculation of the mean.

#### How does variability differ from variance?

Variability is a broader concept that describes general data dispersion without relying on a single formula, unlike the more precise and formula-based variance.

#### What does low variability indicate about a dataset?

Low variability indicates that the data points are closely clustered around the central value, suggesting less dispersion.

#### Why might one use variability measures other than variance?

Other measures of variability might be used for better robustness against outliers or to get an intuitive sense of dispersion in the same units as the data.

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Written by

Maham LiaqatEdited by

Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.