NORM.DIST Function

Basic Description

The Excel NORM.DIST function calculates the Normal Probability Density Function or the Cumulative Normal Distribution Function for a supplied value of x, and a supplied distribution mean & standard deviation. The Norm.Dist function is new in Excel 2010 and so is not available in earlier versions of Excel. However, the function is simply a new version of the Normdist function that is available in earlier versions of Excel.

Syntax: NORM.DIST( x, mean, standard_dev, cumulative )

Where the function arguments are listed in the table below :

x The value at which you want to evaluate the distribution function
mean The arithmetic mean of the distribution
standard_dev The standard deviation of the distribution
cumulative A logical argument which denotes the type of distribution to be used:

TRUE = Cumulative Normal Distribution Function
FALSE = Normal Probability Density Function

 

Note that a mean equal to 0 and a standard deviation of 1 defines the standard normal distribution.

 

Norm.Dist Function Examples

Example 1 – Normal Probability Density Function

The chart on the right shows the the Normal Probability Density Function with a mean of 40 and a standard deviation of 20.

If you want to calculate the value of this function at x = 50, this can be done using the Excel Norm.Dist function, as follows:

=NORM.DIST( 50, 40, 20, FALSE )

This gives the result 0.017603266.

Plot of Normal Probability Density Function with Mean=40 and Standard Deviation=20

  Normal Probability Density Function with mean = 40 & std. dev. = 20
Example 2 – Cumulative Normal Distribution Function

The chart on the right shows the the Cumulative Normal Distribution Function with a mean of 1 and a standard deviation of 0.3.

If you want to calculate the value of this function at x = 0.8, this can be done using the Excel Norm.Dist function, as follows:

=NORM.DIST( 0.8, 1, 0.3, TRUE )

This gives the result 0.252492538.

Plot of Cumulative Normal Distribution Function with Mean=1 and Standard Deviation=0.3

Cumulative Normal Distribution Function with mean = 1 & std. dev. = 0.3

 

Norm.Dist Function Errors

If you get an error from the Excel Norm.Dist function this is likely to be one of the following:

#NUM! Occurs if the supplied standard_dev argument is ≤ 0
#VALUE! Occurs if either the supplied mean or the supplied standard_dev argument is non-numeric

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