Posts filed under “Mathematics”

Wherein I Correct Nobel Laureate Daniel Kahneman’s Math

I am a fan of Morgan Housel, columnist at the Motley Fool. His writings evince a strong understanding of behavioral issues, and he has a gift of sifting through the nonsense to get to what really matters. Only on rare occasions do I get to disagree with him.

Today is one of those times.

Housel has been sporadically posting notes on books he has read. This week, he discussed “6 Things I Learned From the book ‘Thinking Fast and Slow,’” by Princeton psychologist Daniel Kahneman.

Most of the column is solid, with five interesting bullet points. But one of Kahneman’s points leapt out at me as having a small math error: The most important things in life are unpredictable:

The idea that large historical events are determined by luck is profoundly shocking, although it is demonstrably true. It is hard to think of the history of the twentieth century, including its large social movements, without bringing in the role of Hitler, Stalin, and Mao Zedong.

But there was a moment in time, just before an egg was fertilized, when there was a fifty-fifty chance that the embryo that became Hitler could have been a female. Compounding the three events, there was a probability of one-eighth of a twentieth century without any of the three great villains and it is impossible to argue that history would have been roughly the same in their absence. The fertilization of these three eggs had momentous consequences, and it makes a joke of the idea that long-term developments are predictable.

I have no problem with the random aspect of history — yes, many important things in life are unpredictable. The problem with this analysis is that it is mathematically one-sided. As is so often the case, the counterfactual provides insight.

Continues here

 

 

Category: Bad Math, Psychology

Got Math? Odds Are, You Don’t Understand Probabilities

Last week, we discussed the problems with having poor reading comprehension and the impact that has on consuming news. This week, I want to look at the lack of math skills. America seems to becoming a dangerously innumerate society. Innumeracy is incompetence with numbers rather than words. This is a worrisome issue for the future…Read More

Category: Apprenticed Investor, Bad Math, Data Analysis, Really, really bad calls

Why the American economy grows faster under Democrats

Another classic correlation versus causation issue:

Autoplay video after the jump

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Category: Bad Math, Video

Inflation Was Much Higher Pre-Crisis than Post-Crisis

click for ginormous chart Source: FRED     This morning’s column on Inflation truthers led to some emailers insisting inflation numbers are much higher post crisis than pre. Sorry, but the data says that is simply not true. Play with the attached FRED XL spread sheets all you want, the data is hard to argue…Read More

Category: Data Analysis, Inflation, Mathematics

What the World Cup Tells Us About Investing Models

  “All models are wrong; some are useful.” – George E. P. Box   The quote above comes from George Box. He was a brilliant statistician and professor, who thought long and hard about the use and misuse of statistics. I was reminded of Box this weekend while watching the thrilling World Cup final between…Read More

Category: Investing, Mathematics, Sports

Math Is The Ultimate Bull$*&t Detector

 

 

Chances are that when you think about math—which, for most of us, happens pretty infrequently—you don’t think of it in anything like the way that Jordan Ellenberg does. Ellenberg is a rare scholar who is both a math professor (at the University of Wisconsin-Madison) and a novelist. And in his fascinating new book, How Not to Be Wrong: The Power of Mathematical Thinking, he deploys analyses of poetry, politics, and even religion in a bold recasting of what math is in the first place.

For Ellenberg, the stuff you hated about math in high school isn’t the core of the thing. He’s emphatic that mathematics isn’t simply about the calculations involving, you know, numbers; rather, it’s a highly nuanced approach to solving problems that we all, unavoidably, encounter. Ellenberg’s chapters range from showing how mathematical thinking undermines many popular proofs for the existence of God (Paley’s design argument, Pascal’s wager), to explaining how math helps us understand why smoking causes lung cancer (contrary to claims by one early statistician who actually argued that the causation might be reversed—that lung cancer might cause smoking!).

On the show this week we talked to Ellenberg about his book, and math: why you’re probably thinking about it all wrong, and why it’s so powerful.

This episode also features a short interview with Tasneem Raja, author of the must-read new article “We Can Code It: Why computer literacy is key to winning the 21st century” in Mother Jones, and a discussion of new findings about autism and possibly how to stop it—by making brain cells better able to communicate with one another.

Category: Mathematics, Video

Six Ways to Separate Lies From Statistics

From Betsey Stevenson & Justin Wolfers, a short primer on separating lies from statistics:   1. Focus on how robust a finding is, meaning that different ways of looking at the evidence point to the same conclusion. Do the same patterns repeat in many data sets, in different countries, industries or eras? 2. Results that…Read More

Category: Bad Math, Data Analysis, UnScience

Model Risk of Risk Models

Category: Credit, Mathematics, Think Tank

How Do Investors Fight Through Market Noise?

Bloomberg’s Barry Ritholtz examines how investors react to big market moves, the role of fundamental analysis in today’s markets and the recent rough road for IPOs on Bloomberg Television’s “Market Makers.”

Category: Mathematics, Media, Video

Why Are So Many Traders Killing Themselves?

This column is not about working too hard, or the dangers of high cholesterol, or lack of exercise. It is about a rash of suicides within the financial community. What this actually means is less certain than the reporting on it might imply. Yesterday, 47-year-old Edmund Reilly, a trader at the Vertical Group, jumped in…Read More

Category: Bad Math