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.
Difficulty percentage ranges per category and mean value taken for quantitative study.
| Label | Level of Difficulty | Difficulty Range in % | Difficulty Mean Value (%) |
|---|---|---|---|
| 0 | no difficulty | 0% | 0% |
| 1 | light difficulty | 5 to 24% | 14.5% |
| 2 | moderate difficulty | 25 to 49% | 37% |
| 3 | large difficulty | 50 to 95% | 72.5% |
| 4 | total difficulty | 96 to 100% | 98% |
