Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Purcell GxE interaction model. GA1 = twin 1 general ability score; GA2 = twin 2 general ability score; z1 = twin 1 latent GA score; z2 = twin 2 latent GA score; EDU = mid-parent education level. Open circles indicate random effects. GA scores are standardized so that the ACE variance components total 1.0.
