Randomness isn’t in charge of anything: the “hot hand” in basketball

http://wmbriggs.com/blog/?p=731 ^ | William Briggs

[mattstat]

The Wall Street Journal is helping Leonard Mlodinow tout his book The Drunkard’s Walk: How Randomness Rules Our Lives. Among other things, Mlodinow, like academics Tversky, Kahneman, and Gilovich before him, wants to show that streaks in games like basketball don’t exist. Or, rather, they do exist, but they can be “explained by randomness.”

Listen: randomness can’t explain anything.

Statisticians imagine—I choose this word carefully—a basketball player has an ineffable probability of making a free throw, and they try to guess the probability’s value through modeling. Suppose a guess is 80% for a particular player and then suppose our player has just made his last 10 shots. A fan might say our man has a hot hand.

Mlodinow: "If a person tossing a coin weighted to land on heads 80% of the time produces a streak of 10 heads in a row, few people would see that as a sign of increased skill. Yet when an 80% free throw shooter in the NBA has that level of success people have a hard time accepting that it isn’t. [Tversky and others] showed that despite appearances, the 'hot hand' is a mirage. Such hot and cold streaks are identical to those you would obtain from a properly weighted coin."

This statement is confused. Each time a “properly weighted coin” is tossed something makes it fall heads or tails, some physical cause. “Randomness” does not make the coin choose a side....

[The_Media_never_lie]

I get the feeling that someone has way too much time on their hands-maybe it’s just a random thought.