I created six hundred coins. I tell you that each is red on one side, but may be red or blue on the other side. I flip each coin, and show you the resulting colors. You count 400 red and 200 blue. What is your best estimate of the number of coins that are red on both sides?

I flipped all the same coins again, and you count 350 red and 250 blue. How should you modify your estimate?

The blue visible coins should be 50% of the total red/blue coins, so in the first case I'd say there are 400 red/blue and 200 red/red.

In the second case, I'd estimate 500 red/blue and 100 red/red.

Of course, I could also average both results, and end with 450 red/blue and 150 red/red...

Posted by Old Original Oskar! on 2006-12-22 08:53:33