Category Archives: Math
How Does That Work, Again?
I just read that the Chicago Bulls won the NBA draft lottery, meaning that the team with the worst record did not gain the first overall pick in the draft. Color me shocked. It was termed a “surprise” in some stories. Maybe it was a surprise that they won it, but not that the Heat — who, with the worst record had a 25% chance of winning the lottery —didn’t. Before the 1994 draft, the weighting was adjusted to give the team with the worst record a 25% of drafting first. Since that time, the team with a 25% probability has won exactly once: the Orlando Magic in the 2004 draft. (The Cavs in 2003 had a 22.5% chance, by virtue of being tied with Denver for the worst record.)
Whoever ends up in the cellar this year had better be praying for some regression to the mean.
Sweet, Sweet Sampling Error
The candy weighing demonstration, or, the unwisdom of crowds
Get some candies of different sizes and shapes and put them in a bag. Have students estimate the mass of the ensemble by choosing 5 candies, finding their average mass, and multiplying by the number of candies. Their estimate will be too large because their sampling will be biased toward the larger candies.
via God Plays Dice
The NSA Knows You're Reading This
Long but interesting NSA article: Solving the Enigma, including the American contribution of solving the Navy four-rotor Enigma codes.
(And recall a previous post about making a paper Enigma machine)
Top Dog
The Red Baron’s streak was partly skill but mostly luck. “Theory of aces: high score by skill or luck?” by Simkin and Roychowdhury, from the arxiv blog
We find that the variance of this skill distribution is not very large, and that the top aces achieved their victory scores mostly by luck. For example, the ace of aces, Manfred von Richthofen, most likely had a skill in the top quarter of the active WWI German fighter pilots, and was no more special than that.
And while I’m on the topic, there’s an issue with the Royal Guardsmen’s “Snoopy vs. the Red Baron”
Eighty men died tryin’ to end that spree
It wasn’t a spree until after several, or at the very least two, men had died. OK, I’ll accept artistic license.
(and since the Germans required that “The opponent aircraft had to be either destroyed or forced to lend [sic] on German territory and its crew taken prisoners.” in order to be a victory, so when Snoopy was shot down part way through the song, that wasn’t one of the 80.)
A Trend in Need of Investigation
I notice a slowdown in blog posts this weekend. I wonder if anyone has investigated the posting habits of US bloggers as it correlates with the weekend before April 15, which is tax day in the US. I did most of my heavy lifting a few weeks ago, and finished up the last hour or so of details yesterday.
I promise not to depreciate non-taxable items brought forth from the previous tax year!
U.S. Tax system disrupts Casual Friday at Cognitive Daily
A BEAUTIFUL SATURDAY TO DO TAXES
It’s Too Warm to be Doing Taxes
One of the Usual Suspects – I’m sick of doing taxes.
The Weekend Daily Dog: All better now. …the way I felt earlier today while doing taxes
Doing taxes are the death of me
Twitter Updates for 2008-04-12 Doing taxes – yay!
taxes suck
That’s just a few, and not counting anybody who didn’t bother to blog about it, because they were too busy doing their taxes.