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.
Curved arrows represent the propagation direction, dotted curved arrow with an X indicates no propagation, and gray circle (Xa) represents a node where Evidence is given. (a) Model A: Propagation does not occur from Xa to D. (b) Model B: Propagation occurs from Xa to D.
