Suppose your dataset consists of the following points.
(1,5)
(2,3)
(3,10)
(4,4)
Clearly there's really not a linear relationship between the first coordinate and the second coordinate. In other words, if you plot these four points and try to approximate them with a single line in the plane, you just can't do a very good job.
The person's manager suggested sorting the second coordinates in this list while keeping the first coordinates fixed, resulting in the following:
(1,3)
(2,4)
(3,5)
(4,10)
These points are still not collinear, but they certainly can be better approximated by a line than before. The problem is that this is simply a completely different set of points, so a linear approximation here implies nothing about the original dataset.
(1,5)
(2,3)
(3,10)
(4,4)
Clearly there's really not a linear relationship between the first coordinate and the second coordinate. In other words, if you plot these four points and try to approximate them with a single line in the plane, you just can't do a very good job.
The person's manager suggested sorting the second coordinates in this list while keeping the first coordinates fixed, resulting in the following:
(1,3)
(2,4)
(3,5)
(4,10)
These points are still not collinear, but they certainly can be better approximated by a line than before. The problem is that this is simply a completely different set of points, so a linear approximation here implies nothing about the original dataset.