Updated: 9 August 2010

Use NORMDIST to calculate the normal distribution for the specified mean and standard deviation. The formula for the probability density function (pdf) is:

The formula for the cumulative distribution function (cdf) is:

SELECT [wctStatistics].[wct].[NORMDIST] (

<@X, float,>

,<@Mean, float,>

,<@Standard_dev, float,>

,<@Cumulative, bit,>)

is the value at which to evaluate the function. @*X *is an expression of type **float** or of a type that can be implicitly converted to **float**.

is the arithmetic mean of the distribution. @*Mean *is an expression of type **float** or of a type that can be implicitly converted to **float**.

is the standard deviation of the distribution. @*Standard_dev *is an expression of type **float** or of a type that can be implicitly converted to **float**.

is a logical value that determines if the probability density function (False, 0) or the cumulative distribution function (True, 1) is being calculated.

float

· If *@Standard_dev* ≤ 0, NORMDIST returns an error

· If @*Mean* = 0 and *@Standard_dev *= 1 and *@Cumulative *= 'False', NORMDIST = NORMSDIST(*@X*)

Select wct.NORMDIST(-4.6159,10,5,'False')

This produces the following result

----------------------

0.00111280980994974

(1 row(s) affected)

Select wct.NORMDIST(-4.6159,10,5,'True')

This produces the following result

----------------------

0.00173238078965338

(1 row(s) affected)