NORMSDIST function
In Excel 2010, several functions have been implemented with new algorithms for improved accuracy.
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Returns the standard normal cumulative distribution function. The distribution has a mean of 0 (zero) and a standard deviation of one. Use this function in place of a table of standard normal curve areas.
Syntax
NORMSDIST(z)
Z is the value for which you want the distribution.
Remarks

If z is nonnumeric, NORMSDIST returns the #VALUE! error value.

The equation for the standard normal density function is:
Example
The example may be easier to understand if you copy it to a blank worksheet.
How to copy an example

Create a blank workbook or worksheet.

Select the example in the Help topic.
Note Do not select the row or column headers.
Selecting an example from Help

Press CTRL+C.

In the worksheet, select cell A1, and press CTRL+V.

To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.

