7 of 10. I underestimated Asian (Eurasian?) continent area by factor 4 (safety margin one order of magnitude), quantity of US dollars by factor 10 (safety margin 3 orders of magnitude) and volume of gr. lakes by factor 0.1 (safety margin 3 orders of magnitude). Other safety margins were 3 orders of magnitude for Titanic, Pacific coast (fractal-like curves can be very long), book titles, and 0.5 from mean value for others. Sigh, I thought I'll have 90%.
Hm, I estimated area of Asian continent as area of triangle with 10000km base (12 timezones for 20000 km and factor of 0.5 for pole proximity) and 10000km height (north pole to equator), and lost one order of magnitude in calculation.
So you think its important to be able to estimate how well you are estimating something? Here is a fun test that has been given to plenty of other people.
I highly recommend you take the test before reading any more.
http://www.codinghorror.com/blog/2006/06/how-good-an-estimator-are-you.html
The discussion of this test at the blog it is quoted in is quite interesting, but I recommend you read it after taking the test. Similarly, one might anticipate there will be interesting discussion here on the test and whether it means what we want it to mean and so on.
My great apologies if this has been posted before. I did my bast with google trying to find any trace of this test, but if this has already been done, please let me know and ideally, let me know how I can remove my own duplicate post.
PS: The Southern California meetup 19 Dec 2010 was fantastic, thanks so much JenniferRM for setting it up. This post on my part is an indirect result of what we discussed and a fun game we played while we were there.