# Maths question - testing related datasets

**URL:** <https://boards.straightdope.com/t/maths-question-testing-related-datasets/812343>\
**Category:** Factual Questions\
**Created:** [April 13, 2018, 10:21am UTC](https://boards.straightdope.com/t/maths-question-testing-related-datasets/812343 "2018-04-13T10:21:18Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![tigerwoods](https://avatars.discourse-cdn.com/v4/letter/t/e47c2d/32.png) [@tigerwoods](https://boards.straightdope.com/u/tigerwoods)\
**Post date:** [April 13, 2018, 10:21am UTC](https://boards.straightdope.com/t/maths-question-testing-related-datasets/812343/1 "2018-04-13T10:21:18Z")

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Hello people,

I have 3 sets of XY data. In each dataset as you advance in increasing X direction the Y values are scattered above and below the X axis in what appears to be a random fashion. When you plot the 3 datasets at once the scattering looks related. That is, at each X sample point the 3 Y values look to be similarly distributed. How do I test one dataset’s relatedness to the next dataset? And how do I express that relatedness?

As the data in each set is sampled at the same X values as the others I had a mind to run a linear regression through a series of coordinates made of Y(set 1),Y(set 2), and then the other 2 combinations of Y values. My educational background only dealt with fitting trends to singular datasets, but not comparing one set of data to another. And I wouldn’t know how to express relatedness.

Thanks for any replies