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The ShufflePlay Game
Posted By Barry Ritholtz On January 19, 2005 @ 12:27 pm In Finance,Music | Comments Disabled
Last week, we discussed how the iPod Shuffle was the new radio . Its a straight forward thesis, hard to argue against.
Have a gander at a this meme  making its rounds on the net — evincing even more evidence that the radio business model of playing music is fading:
This  week,  we are  discovering  proof  of this  all  over  the
web,  via what’s  been called  The ShufflePlay Game . (I put up my own version of the ShufflePlay Game  over here  and here ).
Here’s a short list of blogs posting variations of Shuffle Play:
The Republic of T . gets props for being the earliest of these I’ve found — dating all the back to April 2, 2004 . Scott’s Place  gets special  mention  for having assembled  at least  7 random  shuffle  collections  (Kudos!).
If you know of any other shuffle play posts, please let me know , and I’ll add them to the list . . .
(listed bloggers feel free to trackback to this post).
Okay, let’s say you have 2500 songs. To simplify, let’s say that’s 10 songs per album for a total of 250 albums. And we’ll define "repeat" as "hearing a song from the same album you’ve already heard a song from". How often will you hear a repeat (by that definition)?
By the time you get to the 20th song, the odds of having heard at least one repeat by the same artists is an extremely surprising 76%!
I’d love to see that math verified . . .
UPDATE: January 24, 2005 6:30 am
Tobias Brandt weighs in on the subject of the Math of shuffle play
"I disagree with Prof. Booty’s analysis of the probability of getting a repeat album within 20 songs and my own analysis puts the odds at 54%. (See spreadsheet  used to get the result). The spreadsheet also has the benefit of being able to account for excluding repeats of previous songs, a feature many media players have.
Prof Booty: Not sure what accounts for your mistake but generally speaking one can’t just sum probabilities and it’s best to look at things like this in terms of a probability tree diagram.
I wish I could get all my questions answered so quickly and succinctly!
UPDATE II: February 6, 2005 11:31 am
If you are curious how the Pod actually makes its shuffle decision, check out:
A Look Inside the iPod Shuffle 
hat tip: iPoditude 
Article printed from The Big Picture: http://www.ritholtz.com/blog
URL to article: http://www.ritholtz.com/blog/2005/01/the-shuffleplay-game/
URLs in this post:
 iPod Shuffle was the new radio: http://bigpicture.typepad.com/comments/2005/01/ipod_shuffle_ne.html
 meme: http://en.wikipedia.org/wiki/Meme
 This: http://yglesias.typepad.com/matthew/2005/01/shuffle.html
 week,: http://bamber.blogspot.com/2005_01_01_bamber_archive.html#110562719302236815
 are: http://grammarpolice.net/archives/000511.php
 discovering: http://www.crescatsententia.org/archives/2005_01_12.html#004924
 proof: http://deathintheafternoon.blogspot.com/2005/01/six-hour-exams.html
 this: http://divineangst.blawgcoop.com/archives/2005/01/my_ipods_shuffl.html
 all: http://www.willwilkinson.net/flybottle/archives/2005/01/shuffle_game.html
 over: http://www.mdcbowen.org/cobb/archives/003245.html
 what’s: http://www.ritholtz.com/blog http://mansfieldfox.blogspot.com/2005/01/know-me-by-my-music.html
 called: http://www.knowledgeproblem.com/archives/001085.html
 The ShufflePlay Game: http://bigpicture.typepad.com/writing/2005/01/shuffle_play.html
 here: http://bigpicture.typepad.com/writing/2005/01/more_shuffle_pl.html
 The Republic of T.: http://republicoft.typepad.com/
 Music for the Masses: http://republicoft.typepad.com/republic_of_t/2004/04/music_for_the_m.html
 Scott’s Place: http://www.matthewman.net/
 Shuffle play: http://www.matthewman.net/archives/2004/04/02/shuffle_play.php
 Matthew Yglesias: http://yglesias.typepad.com/
 essays & effluvia: http://bigpicture.typepad.com/writing/
 The Fly Bottle:: http://www.willwilkinson.net/flybottle/
 Shuffle Game: http://www.willwilkinson.net/flybottle/archives/2005/01/shuffle_game.html
 Stumbling and Mumbling: http://stumblingandmumbling.typepad.com/stumbling_and_mumbling/
 Shuffle and see : http://stumblingandmumbling.typepad.com/stumbling_and_mumbling/2005/01/shuffle_and_see.html
 Crescat Sententia: http://www.crescatsententia.org/
 divine angst: http://divineangst.blawgcoop.com/
 Grammar.police: http://grammarpolice.net/
 Class Maledictorian: http://bamber.blogspot.com/
 Knowledge Problem: http://www.ritholtz.com/blog http://www.knowledgeproblem.com/
 WHILE WE’RE IN A MUSIC VEIN …: http://www.ritholtz.com/blog http://www.knowledgeproblem.com/archives/001085.html
 Mansfield Fox: http://mansfieldfox.blogspot.com/
 Know Me by My Music: http://mansfieldfox.blogspot.com/2005/01/know-me-by-my-music.html
 Death in the Afternoon: http://deathintheafternoon.blogspot.com/
 aworks :: "new" american classical music: http://rgable.typepad.com/aworks/
 Wedge (1961). Roger Reynolds: http://rgable.typepad.com/aworks/2005/01/wedge_1961_roge.html
 Cobb: http://www.mdcbowen.org/cobb/
 special: http://www.matthewman.net/archives/2004/12/04/random_play.php
 mention: http://www.matthewman.net/archives/2004/10/17/ten_random_songs.php
 assembled: http://www.matthewman.net/archives/2004/06/20/random_play.php
 least: http://www.matthewman.net/archives/2004/05/08/random_ten.php
 random: http://www.matthewman.net/archives/2004/03/24/ten_genuinely_random_songs.php
 shuffle: http://www.matthewman.net/archives/2004/03/21/ten_random_songs.php
 know: mailto:firstname.lastname@example.org?subject=Shullf Play
 Professor Booty’s: http://www.bootyproject.org/
 Math of Random/Shuffle Play: http://www.bootyproject.org/show_article.asp?id_article=5075
 spreadsheet: http://bigpicture.typepad.com/comments/files/song_repeat_probability.xls
 A Look Inside the iPod Shuffle: http://www.applematters.com/weblog.php?id=P272
 iPoditude: http://www.ipoditude.com/
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