Detour

Law of the Unconscious Statistician

Def.: If E|g(X)| = ∞ then Eg(X) does not exist.
Cauchy Mean is an example of a random variable whose expected value does not exist.
f(x) = (1/pi)(1/(1+ x^2), -∞ < x < ∞
E(x) = ∞

I wish every law, theorem, and lemma in math and economics were named in such a memorable way. I would have a much easier time remembering what Farka’s Lemma was if it was named the vector idiotic tradition lemma or some such other inane title.

Update: Cecilia Cotton has a multpile choice test to determine if you understood the above law.

“I’m not an outlier, I just haven’t found my distribution yet.” Nice.

Update: Jacqueline thinks objects in multivariable calculus have such funny names.

Adam @ SUNY Stony Brook has started blogging about his journey toward becoming a bona fide economist. Good Luck!

Somebody please slap me for being such a big ignoramus! Sooo many people suggested I read Moneyball, I knew the premise of the book would appeal to me, I loveeeeeeeddd Liar’s Poker, and I have had the book on my bookshelf for almost a year now. I read it in two sittings and already want to read it again.

I was rolling on the floor laughing my brain away when Paul Volcker began asking why finances needed to be changed in baseball.

“If poor teams had no hope, how did the Oakland A’s, with the second lowest payroll in all of baseball, win so many games?”

The other people on the commission to ’save baseball’ couldn’t answer the question so they bring Billy Beane (the GM of the A’s who is using statistical inferences to buy 100 win teams with the money the Yankees were paying for three players), he doesn’t want to tell them how he does it, if he pleads poverty and pain the commission gives him even more money and limits the amount other teams can spend. Billy has every incentive to lie…

“…Billy flew off to New York to explain to Volcker why he was a fluke. He was happy to do it. He hadn’t the slightest interest in stopping the panel from concluding that his life was unfair. He’d be delighted to see the cost of players constrained… he told the panel that no matter how well the team performed the fans stayed away (due to a lack of stars) - which was the opposite of the truth….What he (Billy) believed was what Volcker seemed to suspect, the market for baseball players was so inefficient that superior management could still run circles around taller piles of cash.”

You can guess what the panel decided to do.

Update: Mark Cuban, owner of the NBA’s Dallas Mavericks, has some ideas called MoneyBall for the NBA.

Did you know this existed? It turns out the President of Cornell has been actively involved during his life.

It seems even University Presidents can have too much free time on their hands…I wish graduate students had such a luxurious amount of time in the year.

Global warming approaching point of no return, warns leading climate expert.

Money quote…

“Climate change is for real. We have just a small window of opportunity and it is closing rather rapidly. There is not a moment to lose.”

Guess we should stop using our heaters now.

Dr Rajendra Pachauri’s solution…

Question: The Kyoto Protocol alone will not be enough to stabilize the concentration of GHGs in the atmosphere. What do you think?

Answer:That’s correct. The Kyoto Protocol is a step in the right direction because, for the first time, a large number of countries have decided to take collective action in this regard. However, for all these years we have been focusing on this treaty, without paying attention to the long-term goal: the stabilization of atmospheric GHG concentration. Even if we succeeded in stabilizing emissions within 20 or 25 years, climate change would persist for a century. Realizing something today is simply not enough.

So even if the Kyoto Protocol were to take effect today (with all of the economic impacts that it would create), it would still not be enough…damn! We’re fucked!

Sounds suspiciously like these statements from the 1970’s…

“Suppose we assume, as did weather scientists interviewed by writer Nigel Calder, that the chances of continued cooling and of an Ice Age dawning within a century are one in ten, odds likened by one scientist to Russian roulette. The odds are in our favor, but consider the stakes being wagered: if the cooling continues, we can reasonably calculate that potentially two billion people could starve to death or die of other symptoms of chronic malnutrition by the year 2050. Potentially, we could all die if global famines and embargos on carce resources, both caused by the cooling, lead to a world war. We simply cannot afford to gamble against this possibility by ignoring it. We cannot risk inaction. Those scientists who say we should ignore the evidence and the theories suggesting Earth is entering a period of climaticinstability are acting irresponsibly. The indications that our climate can soon change for the worse are too strong to be reasonably ignored.” —Lowell Ponte in “The Cooling”, 1976

“In ten years all important animal life in the sea will be extinct. Large areas of coastline will have to be evacuated because of the stench of dead fish.” —Paul Ehrlich, Earth Day 1970

“The continued rapid cooling of the earth since WWII is in accord with the increase in global air pollution associated with industrialization, mechanization, urbanization and exploding population.” —Reid Bryson, “Global Ecology; Readings towards a rational strategy for Man”, 1971

Newsweek
April 28, 1975

The Cooling World
There are ominous signs that the Earth’s weather patterns have begun to change dramatically and that these changes may portend a drastic decline in food production– with serious political implications for just about every nation on Earth. The drop in food output could begin quite soon, perhaps only 10 years from now…
…Climatologists are pessimistic that political leaders will take any positive action to compensate for the climatic change, or even to allay its effects. They concede that some of the more spectacular solutions proposed, such as melting the Arctic ice cap by covering it with black soot or diverting arctic rivers, might create problems far greater than those they solve…

The worry then was the irreversible global cooling disaster. At least we have it right now. *cough*

Update: More environmental goblee-gook can be found at P.S.Babcock’s masterful sight Ask Edgeworth. Don’t forget to read the comments, Chris Reicher, as usual, writes more in comments of others people’s blogs then in his own, what a log-linearization jock .

Update: Humans ‘may have saved world from ice age’

The findings from a team of American climate experts suggest that were it not for greenhouse gases produced by humans, the world would be well on the way to a frozen Armageddon.

Update: There are over 70 comments below from people that have solutions manual’s they would like to trade. Post your name and what you have along with your email address so that people can get a hold of you. Good luck getting the solutions you seek.

I have been getting a lot of hits on my site for the solutions to problems. Here is a ampling of search terms (there are many more where this came from)…

mas-collel solutions
solutions manual for microeconomic theory mas-colell on-line
romer solutions manual
mas-collel solution manual
simon blume solutions
mas-colell whinston green solutions
solution chapter 7 mas colell

I have them, but not online…I imagine that if I were to put them online Oxford, McGraw-Hill, and Norton would send their lawyers after me. No thanks!

Update: Note the different spelling’s of Mas-Colell. I have difficulty myself remembering how to spell his name, I say we just rename him ‘evil’ then we can always remember how to spell his name.

Just in case you need an exercise routine for flying long distances, JetBlue has a nifty little exercise card for plane trips.

Update: Chris R. (Log-Linearization Jock) writes…

This is a parody waiting to happen. I’m not that big of a person (skinnier than average, a few inches taller than average) but I’d never be able to find that much room in an airplane seat to move around. I’ll bet that this is a CYA maneuver in order to deny responsibility for deep-vein thrombosis or incipient alcoholism.

“Single leg seat bump” Wait until the guy in front of you, who’s reclined into your stomach, to fall asleep. In a completely jerky motion, thrust your knee into his right kidney. Laugh as he jumps out of his seat and bumps the person in front of him, spilling his drink.

“Fat Guy Armrest Maneuver” If you’re over 250 lb crammed into a middle seat, this one’s for you. During the flight, gradually ooze over the armrest into the sides of the people next to you. Sleep fitfully, jostling your seatmates every time that you roll over in the veal-pen-like environment. Extra points if the rolls of your fat get lodged under the armrests.

“Swollen Bladder Jig” If you’re in a window seat, drink 2 liters of water just before boarding the plane. Imbibe cheerfully whenever the beverage service comes around. Get up at least three times for a walk to the lavatory. Extra points if you do this during severe turbulence and don’t make a mess.

“Plumber Roll Down” Wear low-slung sweatpants or jeans and do the “Roll Down” exercise. Be sure to afford the other travellers in steerage coach a full view of what you’re doing. Now that airlines are cutting back on in-flight entertainment, this will only add to others’ enjoyment of the flight.

“Service Call Swimming” To stretch your arms, hit the service call button every five minutes. The louder the ring, the more often you should do this. Do not confuse this with the light switch, which actually is useful and does not annoy everybody else in the aircraft.

Finally, be sure to enjoy our in-flight magazine. Someone has helpfully pre-filled half of the crossword with wrong answers, just to mix things up a little. Hint: Monay is not a French artist. And since you’re flying to O’Hare by way of Bismarck, read our article about some place in Europe that’s much nicer than where you’re going. You can read about where Michael Jackson stays in Prague, discounted to only $2.53 billion per night. The Hotel Kafka offers the world’s greatest Chateau Petrus bubble bath, enjoyed by shahs and creepy movie stars alike.

In-flight snack (on Transatlantic flights only): Coach: The leftover salt from a bag of pretzels that’s been sitting in the pilot’s cupboard for two weeks. First-class: Seared Japanese purplefish with mango cream aioli and saffron truffle mashed potatoes.

Beverage selections: Coach: Warm RC Cola (1/3-can limit please, on select domestic flights); $5 for premium California Concord grape juice. First-Class: Chateau von Habsburg Tokaji Aszu, 1909; Chateau Latour, 1961, Wood Chip Valley Chardonnay, 1997.

Join our frequent-flyer program! Please note that to redeem miles, call between 4:01 and 4:03 PM every other Thursday, months with “r” excepted. You must book 731 days in advance, and there’s no chance in hell of actually getting to upgrade. Come on, loser. First class is only for corrupt accountants these days. Availability may be limited; reward tickets are only valid for the cargo hold area. You must check in at least 2 days before your flight. Please note that overhead space may be limited, so we will only allow 31 carry-on items, 56″ across, with wheels per passenger. Unless that passenger is you.

I will be flying from Oakland-Denver-Philadelphia-Ithaca on Thursday. Weather forecast in Ithaca tomorrow…

A few clouds. Cold. Low -1F. Winds N at 5 to 10 mph.

That will certainly be the coldest air that my skin has ever felt. Yuck!

My wife, Laura will be staying in the San Francisco Bay Area for a few more weeks to take care of some business. Should give me plenty of time to study and be miserably alone without her. I’ll miss you baby, we’ll be together soon.

Update: Welcome back to Ithaca…Only one question, how can the low be -7 when the temp is currently -8? Also, don’t forget to check out the ‘feels like’ temp…needless to say the trash isn’t going outside tonight!

Mas-Colell, Whinston, Green Exercises, Chapter 3, Microeconomic Theory, Page 100, 3.G.6

After the first two commodities demand functions the problem states
“…where greek letters are non-zero constants.”

The answer then proceeds to declare…

“We must thus have δ = 0”….no errata correction in the solutions manual….ahhhh!

δ still is a greek letter, isn’t it?

I am reviewing Chapter 3 in Mas-Colell and came across this problem from one of our problem sets that always struck me as having an unacceptable answer. Here is the problem…

The TA in her solution sheet just ‘guessed’ (read magiclly came up with the answer with no work shown) that the utility function takes the form u(x,y) = min [x, 2y] and worked the problem from there. I am trying a more documentable route in which I show that the demand fn’s are homogenous of degree zero (HOD 0) and that the substitution matrix is negative semi-definite (NSD) and symmetric (by definition it is because it is a 2 x 2 sub-matrix). Any thoughts on the correctness of this route?