How is linear regression affected by downsampling the explanatory variable?
To be more precise, I would sort all the values of $x$, and then split into a a number bins with equal number of points in each bin (note that each bin may have a different length). Within each bin, I would take the average of both $x$ and $y$ values. The resulting average $y_{avg}$ and $x_{avg}$ would become the new dataset.
I asked a similar question earlier, but then I assumed $x$ has only a few discrete values.