Comment by alexpotato

I was recently looking at a large timeseries dataset.

I noticed when doing a scatter plot of two variables and noticed that there were several "lines" of dots.

This generally implies that subsets of the two variables may have correlations or there is a third variable to be added.

I did some additional research and it is possible for two variables with large N to show correlation for short bursts even if both variables are random.

I mention for two reasons:

1. I was just doing the above and saw the OP article today

2. Despite taking multiple college level stats classes, I don't remember this ever being mentioned.