Fig. 1.
The modified HBM used for data analyses. Solid arrows represent Model 1 analyses. Dashed arrows represent Model 2 analyses.
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.