Dylan, a 3-year-old, comes to your office for an evaluation. You review normative data to determine whether Dylan is developing within normal limits. All of the following statements are reasons you should not over-rely on developmental norms except?
1) norms do not accurately tell us how well a child's sounds are developing
2) a norm is only an average age at which a behavior occurs and refers to a hypothetical child
3) true norms are collected from and apply to a normal, randomly selected sample- these samples rarely exist in the real world
4) different norms are rarely in agreement with each other due to factors such as where or when the study was conducted