Figure 3.
Illustration of the four variables evaluated. Note: (A) steel barrel—empty; (B) steel barrel—full; (C) recyclable barrel- empty; (D) recyclable barrel-full.
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.