Hm. People (at least I do) have a bias towards small numbers. Given the choice, I&#x27;d probably choose something below 20. I don&#x27;t know how representative I am of the general population, but I&#x27;d guess the average to be around 15 and choose 10.<p>--- SPOILER BELOW<p>EDIT: I tested myself on <a href="http:&#x2F;&#x2F;twothirdsofaverage.creativitygames.net&#x2F;" rel="nofollow">http:&#x2F;&#x2F;twothirdsofaverage.creativitygames.net&#x2F;</a> (linked from the wikipedia article) and entered 9. The actual average was 14.