A prediction-making quiz

I just read Ian Ayres' book Super Crunchers, which talks about how the large amounts of data that are now routinely collected enable better predictions than before. Sort of like Freakonomics but a bit more statistical. (Although all the math is hidden -- but I knew that going in.)

Now, there was a recent article The End of Theory which predicts that we don't need theories, we can just mine our data for correlations; I don't believe this. And Ayres talks about how some predictive models need human input -- for example, a model for predicting how Supreme Court justices will vote needs people to read previous input on the cases in order to decide whether the ruling being appealed was liberal or conservative, and also to determine what the major issues involved in the case are. But he ponts out that people are bad at predicting things because we are overconfident about our predictions.

This piqued my curiosity. Here's a quiz; I want to see how good you are at calibrating your own predictions. (This is taken from Ayres' book, p. 113.) For each of the following ten questions, give a range that you are 90 percent confident contains the correct answer. Ayres' test implicitly uses English units, but if you want to use metric (which I suspect a lot of you are more comfortable in) that's fine; I'll convert.

So, for example, if one of the questions were "What is the population of Philadelphia?", and you gave the numbers "1.2 million, 1.6 million", that would indicate that you believe with probability 90 percent that the population of Philadelphia is in that interval. (The 2006 Census estimate for this, by the way, is 1,448,394.)

Your goal is to get exactly nine of these right. Yes, I know that sounds weird! But the point is that if you get all ten right, you're proabably underestimating your own abilities to predict things. If you get eight or less, you're probably overestimating them.

Send your answers to me at izzycat AT gmail DOT com; don't leave them in comments.

Here are the questions:
1. How old was Martin Luther King, Jr. at death?
2. What is the length of the Nile River?
3. How many countries belong to OPEC?
4. How many books are there in the Old Testament?
5. What is the diameter of the moon?
6. What is the weight of an empty Boeing 747-400?
7. In what year was Mozart born?
8. What is the gestation period of an Asian elephant?
9. What is the air distance from London to Tokyo?
10. What is the depth of the deepest known point in the ocean?


Also:
1. feel free to forward this quiz to other people. (I encourage it, although there's a non-negligible chance I might regret this if I get too many answers. I'll survive.)
2. if you have stories about how you made your guess, send them to me; I may use them in a future post.
I'm not going to post the answers; none of them are hard to find. Once answers stop coming in I'll make a post about how good you are at making these predictions.