How do I find the weighted average of a normal vector.
Heres a phrase from my book
a weighted average might be used where the weights are
determined by the areas of the polygons (e.g., polygons with larger areas have more weight than polygons with smaller areas).
Best Answer
The average of a vector $[x_1,x_2,\dots, x_n]$ is calculated simply $$\overline x = \frac{x_1+x_2+\cdots + x_n}{n} = \sum_{i=1}^n\frac{1}{n}x_i$$
If you want to calculate a weighted average, take some set of weights $w_1,w_2,\dots,w_n\geq 0$ such that $w_1+\cdots +w_n = 1$ and calculate the weighted average using the formula
$$\overline{x_w} = \sum_{i=1}^n w_i x_i$$
Notes: