In Excel 2010, the NORMDIST function has been replaced by the NORM.DIST function, which has improved accuracy.
The Excel NORMDIST function calculates the Normal Probability Density Function or the Cumulative Normal Distribution Function for a supplied set of parameters.
The format of the function is :
Where the function arguments are:
|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|
A logical argument which denotes the type of distribution to be used:
Normdist 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 Normdist function, as follows:
=NORMDIST( 50, 40, 20, FALSE )
This gives the result 0.017603266.
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 Normdist function, as follows:
=NORMDIST( 0.8, 1, 0.3, TRUE )
This gives the result 0.252492538.
Cumulative Normal Distribution Function with mean = 1, std. dev. = 0.3
Further information and examples of the Excel Normdist function can be found on the Microsoft Office website.
If you get an error from the Excel Normdist 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|