Related Functions:
The NORM.DIST function returns the normal distribution for the specified mean and standard deviation. This function has a very wide range of applications in statistics, including hypothesis testing.
 This function was introduced in Excel 2010 and so is not available in earlier versions.
 The NORM.DIST function replaces the NORMDIST function included in earlier versions of Excel.
Syntax
=NORM.DIST(x,mean,standard_dev,cumulative)
Arguments
Argument  Description  

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 value that determines the form of the function

Examples
A  B  C  D  

1  Data  Description  
2  20  Value for which you want the distribution  
3  15  Arithmetic mean of the distribution  
4  1.5  Standard deviation of the distribution  
5  
6  Formula  Result  Notes  
7  =NORM.DIST(A2,A3,A4,TRUE)  0.999571  Cumulative distribution function for the terms above  
8  =NORM.DIST(A2,A3,A4,FALSE)  0.001028  Probability mass function for the terms above 
Common Function Error(s)
Problem  What went wrong 

#VALUE!  Occurs if any of the supplied arguments are nonnumeric or nonlogical values 
#NUM!  Occurs if the supplied standard_dev argument is ≤ 0 
The equation for the normal density function (cumulative = FALSE) 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.