# SAS Press» Companion Site

## A Note about Kurtosis

Some readers have questioned whether the kurtosis of a normal distribution is 0 or 3. The confusion results from variations in
the definition of kurtosis. The formula for kurtosis sometimes subtracts 3 (which makes the value for a normal distribution equal to 0),
and sometimes doesn't. SAS software uses the formula that subtracts 3. For details about the formula SAS uses to compute kurtosis and
its significance, see the SAS OnlineDoc by clicking on one of the following links:

**SAS OnlineDoc 9.1.3 for the Web (if you are using SAS 9.0, SAS 9.1, SAS 9.1.2, or SAS 9.1.3)**

http://support.sas.com/onlinedoc/913/getDoc/en/proc.hlp/a002473332.htm

**SAS OnlineDoc Version 8 for the Web (if you are using SAS 8.0, SAS 8.1, or SAS 8.2)**

http://v8doc.sas.com/sashtml/proc/ztatback.htm

You can also search your local SAS Help and Documentation looking for "kurtosis" in the index.