How would you calculate the distance for multi-dimensional data?
From wikipedia:
The distance between any two clusters A and B is taken to be the average of all distances between pairs of objects "x" in A and "y" in B, that is, the mean distance between elements of each cluster:
So if cluster A had point (x1, y1) and cluster B had point (x2, y2), is the mean distance?:
$$\frac{x1-x2}{2}+ \frac{y1-y2}{2}$$
I have no idea what the formula in wikipedia means, i'm math notation illiterate