*Choose Index below for a list of all words and phrases defined in this glossary.*

**Paired T Test** - The two-sample t-test is used to determine if two population means are equal.

The data may either be paired or not paired.

For paired t test, the data is dependent, i.e. there is a one-to-one correspondence between the values in the two samples.

For example, same subject measured before & after a process change, or same subject measured at different times.

For unpaired t test, the sample sizes for the two samples may or may not be equal.

[Category=Data Quality ]

*Source: iSixSigma, 10 February 2011 09:52:47, https: web.archive.org/web/20111109014246/http:www.isixsigma.com/index.php?option=com_glossary *

Data Quality Glossary. A free resource from GRC Data Intelligence. For comments, questions or feedback: dqglossary@grcdi.nl