Related Functions:
The NORM.INV function returns the inverse of the normal cumulative distribution for the specified mean and standard deviation.
 This function was introduced in Excel 2010 and so is not available in earlier versions.
 The NORM.INV function replaces the NORMINV function included in earlier versions of Excel.
Syntax
=NORM.INV(probability,mean,standard_dev)
Arguments
Argument  Description 

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 
Examples
A  B  C  D  

1  Data  Description  
2  0.999571  Probability corresponding to the normal distribution  
3  15  Arithmetic mean of the distribution  
4  1.5  Standard deviation of the distribution  
5  
6  Formula  Result  Notes  
7  =NORM.INV(A2,A3,A4)  20  Inverse of the normal cumulative distribution for the terms above 
Common Function Error(s)
Problem  What went wrong  

#VALUE!  Occurs if any of the the supplied arguments are nonnumeric  
#NUM!  Occurs if either:

The equation for the normal cumulative distribution function is:
where is the mean of the distribution, is the variance, and is the independent variable for which you want to evaluate the function.
See Wikipedia for more information on normal distribution.