New Math vs Old Math

A frequent reader of this blog sent me a link to this video on Facebook, of a side-by-side comparison between a traditional method for doing multidigit multiplication (which is over very quickly) and a new “grid” method (which takes a long time to explain): She wanted to know why anyone would use the long, drawn-out … More New Math vs Old Math

More information doesn’t have to make you more certain

FiveThirtyEight recently posted a piece called “The Impeachment Hearings Just Confirmed Voters’ Preexisting Opinions”: the same wave of new information has just made everybody more convinced of what they already thought: One explanation of this phenomenon is “motivated reasoning”: a person finding data more reliable and arguments more convincing if they fit with what the … More More information doesn’t have to make you more certain

10 percent liable

Last month, this New York Times headline caught my eye for three reasons: Netherlands Was 10 Percent Liable in Srebrenica Deaths, Top Dutch Court Finds Reason #1: Having lived in the Netherlands, headlines about Dutch affairs usually stick out to me. Reason #2: I’d just been reading The Themis Files, a fiction series in which … More 10 percent liable

You’ll never believe what weird trick fixes p-values

Okay, I’m taking a quick break from my regular posts because I can’t stop geeking out about this recent XKCD comic: If you already know about clickbait (likely) and p-values (less likely), you may not need the joke explained to you. But there’s something deep going on here too, tying into the themes of probability … More You’ll never believe what weird trick fixes p-values

If you have a question, someone else probably has it too…

I often tell my students, “When you have a question, ask, because you’re probably not the only one who’s wondering.” I heard the same thing when I was a student, but I still felt embarrassed to ask. What if I really was the only one? Wouldn’t I be slowing down class to ask? If no … More If you have a question, someone else probably has it too…

Cantor’s Arch

Triumphal Arch: Arch of Titus, Rome Arc de Triomphe, Paris Washington Square Arch, New York Triple Arch: Arch of Constantine, Rome Arc du Carrousel, Paris Marble Arch, London Septuple Arch: ??? Cantor’s Arch: It seems to me that no arch is more triumphant than one that rests on a set of measure zero.

Spontaneous Inequality

A fun problem making the mathematical rounds: if you give everybody some number of dollars (say you give 45 people $45 each), and at every tick of the clock everyone with money chooses one random person $1, how will the money eventually end up distributed? You might think it’ll stay approximately equal—”approximately” only because of … More Spontaneous Inequality