Property	Value
Hex Value	`$BB1F`
Categories	Catalog > R Math > Probability
Localizations	FR: `normAléat(`

`randNorm(`

Overview

Generates and displays a random real number from a specified Normal distribution specified by μ and σ for a specified number of trials numtrials.

Availability: Token available everywhere.

Syntax

randNorm(μ,σ[,numtrials])

Arguments

Name	Type	Optional
μ
σ
numtrials

Location

math, PRB, 6:randNorm(

Description

randNorm(µ,σ) generates a normally-distributed pseudorandom number with mean µ and standard deviation σ. The result returned will most probably be within the range µ±3_σ_. randNorm(µ,σ,n) generates a list of n normally-distributed pseudorandom numbers with mean µ and standard deviation σ.

seed→rand affects the output of randNorm(.

0→rand
     0
randNorm(0,1)
     -1.585709623
randNorm(0,1,3)
     {-1.330473604 1.05074514 -.0368606663}

Although a theoretical normally distributed variable could take on any real value, numbers on a calculator have a limited precision, which leads to a maximum range of approximately µ±7.02_σ_ for values of randNorm(.

Optimization

When the mean is 0 and the standard deviation 1, invNorm(rand) and invNorm(rand(N)) save space over randNorm(0,1) and randNorm(0,1,N) respectively.

Formulas

The value of randNorm( for a given seed can be expressed in terms of rand:

randNorm(µ,σ)=µ-σinvNorm(rand

This is identical to the output of randNorm( in the sense that for the same seed, both expressions will generate the same random numbers.

The following formula can be used to get a target interval where A and B are two real intervals.

µ=(A+B)/2
σ=(-A+B)/6

Source: parts of this page were written by the following TI|BD contributors: DarkerLine, GoVegan, MrTanookiMario, Silver Phantom, Timothy Foster, Weregoose.

History

Calculator	OS Version	Description
TI-83	0.01013	Added

Authors: Adrien Bertrand

randNorm(