# Assumption of independence of two correlations for the purpose of a statistical test of the difference.

I'm having a bit of difficulty grasping the concept of 'independence' for the purpose of testing whether two correlations significantly differ from one another (Zou, 2007).

Consider the following made-up example from a sample of adolescents randomly selected from a school:

1. Student BMI (kg/m2) is correlated with a non-expert rating of diet quality (i.e., each individual has their diet rated by non-experts).

2. Student BMI (kg/m2) is correlated with an expert rating of diet quality (i.e., each individual has their diet rated by experts).

In this instance, is it appropriate to assume that each correlation is independent of one another and come from separate groups (although BMI from the same individuals features in each correlation)? The purpose of this would be determine if each correlation significantly differs from one another using the Zou method.