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.
Solid lines correspond to the best-fitted models. Dashed lines correspond to models that fit equally to the null model. The grey area corresponds to the confidence interval around the threshold value.
