What is random numbers? - Definition from WhatIs.com
Part of the Mathematics glossary:

Random numbers are numbers that occur in a sequence such that two conditions are met: (1) the values are uniformly distributed over a defined interval or set, and (2) it is impossible to predict future values based on past or present ones. Random numbers are important in statistical analysis and probability theory.

The most common set from which random numbers are derived is the set of single-digit decimal numbers {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}. The task of generating random digits from this set is not trivial. A common scheme is the selection (by means of a mechanical escape hatch that lets one ball out at a time) of numbered ping-pong balls from a set of 10, one bearing each digit, as the balls are blown about in a container by forced-air jets. This method is popular in lotteries. After each number is selected, the ball with that number is returned to the set, the balls are allowed to blow around for a minute or two, and then another ball is allowed to escape.

Sometimes the digits in the decimal expansions of irrational numbers are used in an attempt to obtain random numbers. Most whole numbers have irrational square roots, so entering a string of six or eight digits into a calculator and then hitting the square root button can provide a sequence of digits that seems random. Other algorithms have been devised that supposedly generate random numbers. The problem with these methods is that they violate condition (2) in the definition of randomness. The existence of any number-generation algorithm produces future values based on past and/or current ones. Digits or numbers generated in this manner are called pseudorandom.

Statisticians, mathematicians, and scientists have long searched for the ideal source of random numbers. One of the best methods is the sampling of electromagnetic noise. This noise, generated by the chaotic movements of electrons, holes, or other charge carriers in materials and in space, is thought to be as close to "totally random" as any observable phenomenon.

This was last updated in September 2005
Posted by: Margaret Rouse

Related Terms

Definitions

  • unique identifier (UID)

    - A unique identifier (UID) is a numeric or alphanumeric string that is associated with a single entity within a given system. (WhatIs.com)

  • quant (quantitative analyst)

    - A quant (quantitative analyst) is a financial services professional whose qualifications also include advanced mathematics and and computer skills. Quants design complex mathematical models for us... (WhatIs.com)

  • statistical analysis

    - Statistical analysis is a component of data analytics. In the context of business intelligence (BI), statistical analysis involves collecting and scrutinizing every single data sample in a set of i... (WhatIs.com)

Glossaries

  • Mathematics

    - Terms related to mathematics, including definitions about logic, algorithms and computations and mathematical terms used in computer science and business.

  • Internet applications

    - This WhatIs.com glossary contains terms related to Internet applications, including definitions about Software as a Service (SaaS) delivery models and words and phrases about web sites, e-commerce ...

Ask a Question. Find an Answer.Powered by ITKnowledgeExchange.com

Ask An IT Question

Get answers from your peers on your most technical challenges

Ask Question

Tech TalkComment

Share
Comments

    Results

    Contribute to the conversation

    All fields are required. Comments will appear at the bottom of the article.