Let’s start with something easy and understandable to analyze. If I put age on the horizontal axis and weight on the vertical axis. It’s a common practice to put an explanatory variable on the horizontal axis and a response variable on the vertical axis. In other words, I’m looking to see how an increase in age (explanation) affects – or not – weight (response) for all the hockey players in the current season, regardless of team.
If I put age on the horizontal axis – does this explain weight? Sort of – the combinations of age and weight have some groupings. It almost appears that there is a greater number of younger, heavier players than older, heavier players, but it’s hard to tell here how the age/weight combinations are distributed because I can’t see all the individual points.
Read the whole thing, while keeping in mind that correlation does not imply causation.