Browse Definitions :
Definition

outlier

Contributor(s): Matthew Haughn

An outlier is a single data point that goes far outside the average value of a group of statistics. Outliers may be exceptions that stand outside individual samples of populations as well. In a more general context, an outlier is an individual that is markedly different from the norm in some respect.

Outliers are an important factor in statistics as they can have a considerable effect on overall results. In especially small sample sizes, a single outlier may dramatically affect averages and skew the study's final results.

An outlier can happen due to disinformation by a subject, errors in a subject's responses or in data entry. In some cases, it's clear that outliers should be removed as errors. In others, it may come down to standards or judgment calls where outliers are a natural deviation.

Statisticians, who often attempt to mitigate the effect of outliers, have come up with ways to identify what makes an outlier. For example, in a scatter plot where data points are graphed, outliers are visually identifiable. In a box plot, outliers are found by using equations to find if they exceed defined norms.

Outliers can sometimes indicate errors or poor methods of sample gathering. They can also indicate an anomaly or something of interest to study since it's not always possible to determine if outliers are in error. Although the effects of outliers can skew results of statistics, it is rare that they are entirely removed from results without observations.

This was last updated in February 2018

Continue Reading About outlier

Join the conversation

1 comment

Send me notifications when other members comment.

Please create a username to comment.

How challenging is it to statistically measure application performance?
Cancel

-ADS BY GOOGLE

File Extensions and File Formats

Powered by:

SearchCompliance

  • PCI DSS (Payment Card Industry Data Security Standard)

    The Payment Card Industry Data Security Standard (PCI DSS) is a widely accepted set of policies and procedures intended to ...

  • risk management

    Risk management is the process of identifying, assessing and controlling threats to an organization's capital and earnings.

  • compliance framework

    A compliance framework is a structured set of guidelines that details an organization's processes for maintaining accordance with...

SearchSecurity

  • Trojan horse (computing)

    In computing, a Trojan horse is a program downloaded and installed on a computer that appears harmless, but is, in fact, ...

  • identity theft

    Identity theft, also known as identity fraud, is a crime in which an imposter obtains key pieces of personally identifiable ...

  • DNS over HTTPS (DoH)

    DNS over HTTPS (DoH) is a relatively new protocol that encrypts domain name system traffic by passing DNS queries through a ...

SearchHealthIT

  • telemedicine (telehealth)

    Telemedicine is the remote delivery of healthcare services, such as health assessments or consultations, over the ...

  • Project Nightingale

    Project Nightingale is a controversial partnership between Google and Ascension, the second largest health system in the United ...

  • medical practice management (MPM) software

    Medical practice management (MPM) software is a collection of computerized services used by healthcare professionals and ...

SearchDisasterRecovery

SearchStorage

  • M.2 SSD

    An M.2 SSD is a solid-state drive (SSD) that conforms to a computer industry specification and is used in internally mounted ...

  • kilobyte (KB or Kbyte)

    A kilobyte (KB or Kbyte) is a unit of measurement for computer memory or data storage used by mathematics and computer science ...

  • virtual memory

    Virtual memory is a memory management capability of an operating system (OS) that uses hardware and software to allow a computer ...

Close