I'm using this 'clickhappier-archive' account to post archival copies of old MTurk-related userscripts from userscripts-mirror.org (which is itself an archive of the defunct site userscripts.org) and forum posts, which their authors or others haven't re-posted on Greasyfork yet. Some of these may no longer be all that interesting as more recent scripts may do what they do better, but some remain very useful.
This script was archived from http://userscripts-mirror.org/scripts/show/449358
Author: Austin3600 aka WoLF
Script Name: MTurk Worst & Best Case Scenario
Last update Apr 17, 2014 — Installed 363 times. [plus ~968 times under swole_hamster's former GF posting of it, removed 01-21-2015]
Script Summary: This script calculates both the worst case and best case scenario of your pending HITs. It displays the results on the dashboard page of MTurk. ... Please REMOVE any other Worst Case / Best Case Scenario scripts you've used before. This replaces both of them (including the patched version I put up a few days ago). If you want to change the "GOOD" and "OK" percentages, edit the script. I've included instruction in the script that tells you what two things to change. ...
Note from Clickhappier: I've personally used this script for months with no problems. This is a more-informative alternative to MTurk Worst Case Scenario Calculator 3.2 and 3.1.
See also: explanation of MTurk Stats Math; related scripts: MTurk Dashboard Change Notifier (with 12-value mod), mmmturkeybacon Add Hidden Stats to Dashboard, CH Export MTurk Quals, CH Precise Percents
For many more MTurk-related userscripts, see the Turking Scripts set.