Slashdot Mirror
How Well Do You Estimate?
A random UK blogger has published a quiz asking readers to estimate various numeric values which they may or may not have knowledge of; and has analyzed the resulting answers to determine how well people guess. The first part of the results looks at some specific questions, and the second part takes a look at the quiz overall.
I estimate that I would end up somewhere in the middle.
With 44.7% accuracy!
more or less.
I am one of many. My idea is not unique, nor do I expect my voice alone to sway you. I speak in a chorus of opinion.
I would estimate that that server stayed up less than 2 minutes after the story was published. Mirrors anyone?
that I will get a +3, funny
Don't waste your vote! Vote for whoever you want, unless you live in a swing state it won't matter anyways
Server timed out trying to contact ex-parrot.com.
Looks like we've got an ex-webserver on our hands.
.
.
"It's not dead, it's IIS!"
Does nobody here on Slashdot even remember the Mythical Man Month any more? The section on estimation and back of the envelope calculations (which I wouldn't be surprised if this blog pulled from, but I can't tell because its slashdotted already) was quite enlightening. Its main point was that people were way too confident in their estimates, even when they would admit that they had no idea.
You're special forces then? That's great! I just love your olympics!
Tony Benn is a Labour politician in the UK.
that we'll end up with about 30 comments about how fast the site went down due to slashdotting....
I can usually estimate within plus or minus one or two Libraries of Congress every time.
I estimate that at about this point all the jokes about estimating will get tedious
Philip
Signatures are broken
google cache of second link http://216.239.39.104/search?q=cache:DB1CxyRtiNsJ: ex-parrot.com/~chris/wwwitter/20040903-but_i_wore_ the_juice.html+ex-parrot.com+/~chris/wwwitter/2004 0903-but_i_wore_the_juice.html&hl=en&start =1
I'm currently taking a course at my school, for essentially doing computations, but only up to a certain accuracy (estimation with precision). We basically build algorithms, that are normally simple enough to follow, and then just repeat the process until the desired precision is reached. There are multiple ways to do estimation. Like for square roots, you can actually used Fixed Point Iteration(x = g(x)), where g(x) = (x+x/n)/2, where n is the integer of the square root. Just continue that process for about 5 times, and the results are amazing.
je suis parce que j'aime
Reminds me of a bit of training from my army days.
If you have difficulty estimating a distance ( range), divide the distance in two, and try estimating that.
This sounds stupid, but actually works. Well, it worked for me. I'll never forget how I laughed in my head at the suggestion, and my astonishment at it actually working.
Mike.
Part 1
Part 2
I used to work at a small datamining shop. The people there were very bright, some of them quite famous in the fields of statistics, number theory, etc.. One day, we were sitting in the front room of our offices having lunch, chewing the fat, as it were.
At lunches, we would sometimes try to stump our CTO a grey beard who is famous for work in information theory and general genius. We had never succeeded, even with obscure questions in biology "How do Prions work?", physics "What order are the colors of the rainbow, and why?", "How does the Corriolus effect work?", etc. that none of us had any particular knowledge of, and always had to research afterwards to determine the correctness of his answers.
So, I posed the question to the group "How many leaves are on that tree outside the window?" It was a ~30 foot tall, bushy tree in the height of summer. I hoped he'd take the bait.. I thought this was going to be very hard to "get right", and it would even be difficult come up with a plausible answer.
After a few moments, I set off the responses by saying that I thought it easily had 10k leaves, possibly 20k or more.
Everyone gasped. "Oh no! No way..." and then proceeded to offer lower and lower estimates.
The responses started with me and made their way up in the seniority ranks (I was the most junior) all the way up to the CTO. He said "Oh! those kinds of things are notoriously hard to estimate. We typically overestimate grossly in counting things of plentitude. Oh, I don't know. 200?".
Finally we had him. There was no way there were 200 leaves on that tree.
Later, in discussion, a trend became clear. The more senior the person, the more conservative was their response, even to the ridiculous level of our CTO saying a tree in full flush, that he could see right outside of the window, had 200 leaves, when it most plainly had many, many more.
Anyone want to hazard a guess? How many leaves on say, an adult Sycamore (or Maple, Oak, etc.)?
The article's slashdotted, so I'm not sure what this is all about. But I've always prided myself on my ability to estimate time and miles. Frequently, I'll look at my watch and find it's, say, 3:00. Some time later I'll estimate that it's 4:22, look at my watch, and find it's 4:20.
Similarly, I will look at the odometer in my car, drive a distance, and guess that it's 10 miles later. Looking down, 10.1.
The best is when you combine them. "How long before we get there?" the wife asks. "About 47 minutes," say I, and 47 minutes later arrive at our destination.
I note this only because most everyone else seems incredibly bad at this. As when someone gives you loose directions to a place like this, "Oh, go about 3 miles, then turn left on Main St." Half a mile later I'm slamming on the breaks 'cause I just past a sign saying "Main St." Or when they tell you it's a 5 minute drive, when it's really 15. Drives me batty.
In short, I estimate that just about everyone sucks at estimating. Funny thing is people always over-estimate distance and under-estimate time.
Yeah, I know everybody is after funny mods, but you don't "estimate" a future event, you predict it.
Estimation is making an educated guess at a quantity without scientifically measuring it, usually with some sort of observation.
"I reckon thats 8 inches long and 2 inches thick."
Prediction is using past experience to state that an event will happen.
Norman Cook's Ode to Sl
As almost every single comment up until now talks about personal experiences or makes stupid jokes, I'm going to critique the method he uses to score an answer. From the second link (find a google cache of it to read it) you can see that he treats each answer and estimate of the accuracy of the answer as a single question - you get a single score from both. I think this approach is fundamentally flawed. Why not instead score the guess (with some sort of algorithm like the one he uses) and then score the guess of accuracy by the same method. Then if you want a single number, add the two together. Right now if you guess well and guess your accuracy perfectly, you get zero points. That is completely out of whack. Instead, using my way you score the best possible score when you guess perfectly and perfectly guess your accuracy, and the worst possible score when you guess horribly and horribly guess your accuracy. The scores move between those two extremes rationally too. As he wanted people who guessed zero error (thought their guess was a perfect guess) to get no points, he obviously had an agenda - that people should be penalized for thinking they are perfectly right. In no way is this an unbiased or useful test.
I submitted this story last night, and it didn't get posted.
I guess it depends on if the chute opens or not
They spend a lot of time on grouping. For example What is 97 + 198? I was taught to add 8 and 7, carry the one etc...
They are taught to group the numbers, the instantly recognize that the answer is close to 300, then see how it differs from the 100s. 97 is 3 less, 198 is 2 less. Now add the 3 and 2, getting 5.
The answer is of course 300 - 5, or 295.
I find this method very intuitive.
On a side note, there are many errors made when newspapers, magazines, etc. estimate numbers. Sometimes they will round values before presenting the final number, causing a huge difference. Or they will give some value like $6,021.50 when some of the values have only two or three significant digits. Or they'll make some hideous stats error such as adding two means together and not weighting the scores appropriately. An excellent book that discusses this is John Allen Paulos' "A Mathematician Reads the Newspaper."
A former co-worker was telling us about some of her tutoring experiences. She was helping some high school kids with the concept of estimation. She looked at the ceiling and said you could estimate that it was about 10 feet high. She told them that "the great thing about estimation is that it doesn't have to be the 'right' answer."
So she pointed a car parked nearby and asked one of the students how far he thought the car was. His reply, "50 gallons."
Incredulous, she said that his answer didn't make sense.
"But that's the great thing about estimation! It doesn't have to be right!"
-- Don't Tase me, bro!
This issue has been studied for many decades in order to help organizations minimize losses on bad bids. Courses are taught on this. I took something like this once. There was an exercise to estimate the number of beans in jar. People's guesses fell along a curve called the binnormal distribution. From this equation you can estimate the best price to offer versus other people's bids in order to ocassionally win and make money at it.
Reminds me of some work done by psychologists Kahneman and Tversky (Kahneman went on to win the nobel prize in economics for different studies). In their studies they had people do things like this (e.g., what year was the constitution adopted by the states). Supplying "anchors" influences your judgement. For example, supplying the anchor that the articles of confederation were ratified in 1781 (I think) would shift the answer toward 1781 compared with the case in which the anchor was that George Washington left office in 1796. The idea is that if you know a.) that the constitution came after the articles of confederation and b.) that the constitution was ratified before Washington left office, you will use specific dates associated with those events to anchor your answer.
A fine quiz, but I hope he throws out his non-UK results by IP before he uses the data. For many of those topics, my poor American brain had no basis for an estimate and knew it.
The data could be improved by adding the a "no-confidence" checkbox to each question in addition to demanding a numeric answer. With this, he could compare whether people's estimates were better or worse where they thought they knew the answer. This would make a nice complement to measuring raw estimating power.
"We reject as false the choice between our safety and our ideals." --The American President (20.1.2009)
If you're need quick karma, do the following:
1. Post only to new discussions - those with less than 30 comments.
2. Do not reply to main story - instead reply to the first highly modded post.
3. Quote lots of facts or say something political (but keep it loosely on topic and don't use inflammatory statements or you'll get modded a troll).
4. Make your posts long. Long posts are always "Interesting". It's axiomatic.
This will probably get modded Offtopic but since I've got karma to burn and I know how to get it back - I don't think I really care.
I've made up my mind and now I've got to lie in it.