5 ms·
From the article The experiment Over the Spring 2009 semester two Berkeley undergraduates, Priscilla Ku and Janet Larwood, undertook to do the required 40,000
by frogger8 4y ago
From the article
The experiment
Over the Spring 2009 semester two Berkeley undergraduates, Priscilla Ku and Janet Larwood, undertook to do the required 40,000 tosses. After preliminary experimentation with practical issues, there was formulated a specific protocol, described in detail below. Cutting to the chase, here is the complete data-set as a .xlsx spreadsheet (see sheet 2). This constitutes a potentially interesting data-set in many ways -- one could compare numerous theoretical predictions about pure randomness (lengths of runs, for instance) with this empirical data. For the specific question of dynamical bias, the relevant data can be stated very concisely
of 20,000 Heads-up tosses (tossed by Janet) 10231 landed Heads
of 20,000 Tails-up tosses (tossed by Priscilla) 10014 landed Tails
- deleted 4y ago[deleted]
- gus_massa 4y agoFrom https://www.wolframalpha.com/input/?i=binomial+distribution+n%3D20000%2C+p%3D0.5 https://www.wolframalpha.com/input/?i=binomial+distribution+... the standard deviation is almost 71, so it's a 3.3 sigma for Janet and .2 sigma for Priscilla. Since this is not particle physics, we can conclude that Janet (or her coin) is doing something wrong.
- mjburgess 4y agop isnt 0.5, which is the point of the article cf. https://www.wolframalpha.com/input?i=binomial+distribution+n%3D40000%2C+p%3D0.508 https://www.wolframalpha.com/input?i=binomial+distribution+n...
- mjburgess 4y agoIf there is the theoretical 50.8% we would expect 20,230 same-face-up in 40,000 flips. We find here 20,245. Pretty compelling.
- zeroonetwothree 4y agoThe data is consistent with a hypothesis that there is some smaller bias in favor of the side you started with (say 50.4%) and an additional bias in favor of heads (say 50.4%).