IGNORE THIS. We are never going to calculate correlation by hand (because computers are better at it than us anyway).

Bi-variate just means two variables.

Histograms aren't particularly helpful for understanding correlation, but you will be using them to describe your own data in your report.

We'll be talking about this a lot more when we explore the difference between correlation and causation.

The main point here is: just because two variables are correlated, doesn't mean that one variable causes the other.

Remember that we talk about the strength of a correlation between two variables.