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.
An example of a case where multiple windows are required to capture change over time; in this case, target proportion interacts with time. Two or more windows are required to capture this interaction, but window selection is problematic (see text).
