NORMINV Function

Basic Description

The Excel NORMINV function calculates the inverse of the Cumulative Normal Distribution Function for a supplied value of x, and a supplied distribution mean & standard deviation.

Syntax: NORMINV( probability, mean, standard_dev )

Where the function arguments are:

probability The value at which you want to evaluate the inverse function
mean The arithmetic mean of the distribution
standard_dev The standard deviation of the distribution


Norminv Function Example

Excel uses an iterative method to calculate the Norminv function and seeks to find a result, x, such that:

NORMDIST( x, mean, standard_dev, TRUE ) = probability


Plot of Inverse Normal Cumulative Distribution Function with Mean=5 and Standard Deviation=2

Inverse Normal Cumulative Distribution with mean = 5 & std. dev. = 2

The chart on the right shows the the Inverse Normal Cumulative Distribution Function with a Mean of 5 and a Standard Deviation of 2. If you want to calculate the value of this function when probability = 0.6, this can be done using the Excel Norminv function, as follows:

=NORMINV( 0.6, 5, 2 )

This gives the result 5.506694206.


Norminv Function Errors

If you get an error from your Excel Norminv function this is likely to be one of the following:

#NUM! Occurs if either:
–   the supplied probability argument is < 0 or > 1
–   the supplied standard_dev argument is ≤ 0
#VALUE! Occurs if any of the the supplied arguments are non-numeric.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>



clearPost Comment