# Pairwise comparison between samples

**URL:** https://forum.qiime2.org/t/pairwise-comparison-between-samples/7056
**Category:** General Discussion
**Created:** [November 18, 2018, 9:36pm UTC](https://forum.qiime2.org/t/pairwise-comparison-between-samples/7056 "2018-11-18T21:36:11Z")
**Posts on this page:** 1
**Showing post:** 4

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### Author: ![Mehrbod\_Estaki](https://forum.qiime2.org/user_avatar/forum.qiime2.org/mehrbod_estaki/32/4001_2.png) [@Mehrbod\_Estaki](https://forum.qiime2.org/u/Mehrbod_Estaki)
#### Post date: [November 20, 2018, 10:16am UTC](https://forum.qiime2.org/t/pairwise-comparison-between-samples/7056/4 "2018-11-20T10:16:56Z")

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Hi @lca123,  
If you are referring to biological replicates then the answer is the same as above, you can't actually compare variance across groups if there is no variance (i.e. one sample in a group). If you are referring to technical replicates however, that's a whole other story. There is already a discussion regarding technical replicates happening [here](https://forum.qiime2.org/t/the-effect-of-duplicate-and-triplicate-samples-in-16s-downstream-analysis/7029) which I think is where any further discussion should jump to 👍

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