Some Simple Full-Range Inverse-Normal Approximations

Two approximations are given for numerically inverting the full range of the standard normal cumulative distribution function. The first approximation has two fitted constants and only modest accuracy but is very simple and well suited for hand calculators. The second approximation has four fitted...

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Main Author: Raymond Koopman
Format: Article
Language:English
Published: Publishing House of the Romanian Academy 2025-01-01
Series:Journal of Numerical Analysis and Approximation Theory
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Online Access:https://www.ictp.acad.ro/jnaat/journal/article/view/1434
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author Raymond Koopman
author_facet Raymond Koopman
author_sort Raymond Koopman
collection DOAJ
description Two approximations are given for numerically inverting the full range of the standard normal cumulative distribution function. The first approximation has two fitted constants and only modest accuracy but is very simple and well suited for hand calculators. The second approximation has four fitted constants and is more accurate. Alternate versions of the approximations are also given, with the constants chosen to minimize the maximum relative error in the implied approximate q rather than the maximum absolute error in the approximate z.
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institution Kabale University
issn 2457-6794
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language English
publishDate 2025-01-01
publisher Publishing House of the Romanian Academy
record_format Article
series Journal of Numerical Analysis and Approximation Theory
spelling doaj-art-56ca746f359c4d2b92dd537f613ef5212025-02-10T14:49:36ZengPublishing House of the Romanian AcademyJournal of Numerical Analysis and Approximation Theory2457-67942501-059X2025-01-0110.33993/jnaat541-1434Some Simple Full-Range Inverse-Normal ApproximationsRaymond Koopman0https://orcid.org/0000-0003-3977-8939Simon Fraser University, Canada Two approximations are given for numerically inverting the full range of the standard normal cumulative distribution function. The first approximation has two fitted constants and only modest accuracy but is very simple and well suited for hand calculators. The second approximation has four fitted constants and is more accurate. Alternate versions of the approximations are also given, with the constants chosen to minimize the maximum relative error in the implied approximate q rather than the maximum absolute error in the approximate z. https://www.ictp.acad.ro/jnaat/journal/article/view/1434numerical approximationinverse normal distribution functioninverse error function
spellingShingle Raymond Koopman
Some Simple Full-Range Inverse-Normal Approximations
Journal of Numerical Analysis and Approximation Theory
numerical approximation
inverse normal distribution function
inverse error function
title Some Simple Full-Range Inverse-Normal Approximations
title_full Some Simple Full-Range Inverse-Normal Approximations
title_fullStr Some Simple Full-Range Inverse-Normal Approximations
title_full_unstemmed Some Simple Full-Range Inverse-Normal Approximations
title_short Some Simple Full-Range Inverse-Normal Approximations
title_sort some simple full range inverse normal approximations
topic numerical approximation
inverse normal distribution function
inverse error function
url https://www.ictp.acad.ro/jnaat/journal/article/view/1434
work_keys_str_mv AT raymondkoopman somesimplefullrangeinversenormalapproximations