Figure 3.

(a) Simple and conditional bases for two traits in a population (grey dots denote individuals) in which the traits are positively correlated. The simple bases are just the trait values with the means subtracted out. The conditional bases are constructed so that ${\mathbb{P}}_{\bullet }^1$ is orthogonal to ${\mathbb{P}}^2$, and ${\mathbb{P}}_{\bullet }^2$ is orthogonal to ${\mathbb{P}}^1$. (Note that, because ϕ₁ and ϕ₂ are correlated, orthogonality does not correspond to right angles in this system.) (b,c) Projection of the points into the two pairs of orthogonal bases. (Online version in colour.)