Figure 13.
TF BW. Conventions are as in Figure 5. Data for V1 are from Foster et al. (1985) and for V2 from Foster et al. (1985) and Levitt et al. (1994a).
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.