Archive for August, 2009
Making random decisions on the basis of a coin flip
Posted by mark in Basic stats & math on August 28, 2009
I watched the movie Leatherheads last night – a comedic tribute to the early days of professional football. It re-created the first coin flip used to determine which team would kick off. The referee allowed the coin to fall to the ground – introducing a bit more randomness into the outcome (as opposed him catching it). That’s one of the findings presented in the Dynamical Bias in the Coin Toss by a trio of mathematics and statistics professors from Stanford and UC Santa Cruz. Surprisingly, they report that for “natural flips” the chance of a coin coming up as started is 51 percent. In other words, this procedure for creating an even probability is biased by the physics.
My “heads up” (ha ha) on this came from a former colleague of mine. He sent me a link that led me to this flippant (pun-intended) summary by blogger James Devlin . Devlin warns against spinning a coin to create a 50/50 outcome – a heavy-headed coin can fall tails-up as much as 80 percent of the time! It seems to me that this approach would also increase the odds of a flipistic singularity – normally very rare (1 in 6000 chance).
Another colleague, who once collected comics about Donald Duck, told me the tale of flipism – a random way to live life. However, I think I will not go down this road, but rather quit this blog while I am still ahead.
“Life is but a gamble! Let Flipism chart your ramble.”
– Slogan in Flip Decision by Carl Barks
PS. A fellow trainer starts off statistics workshops with a fun icebreaker that gets students involved with flipping a coin. He asks the class what they expect for an outcome and then challenges this assumption experimentally. The first student gets heads, which the trainer tallies on a flipchart. Each student in turn gets the same outcome until someone finally gets suspicious and discovers that it’s a two-headed quarter.
Are you happy? If so, be careful not to laugh: It may trigger gelotophobia!
Posted by mark in Uncategorized, Wellness on August 20, 2009
Check out this freely posted study by math & stats profs Dodds & Danforth (“D&D”) on Measuring the Happiness of Large-Scale Written Expression: Songs, Blogs, and Presidents. Or for a simpler synopsis, see this spin by PHYSorg.com, which harkens back to a utopian dream of “hedonometers” measuring happiness. Not surprising, the D&D hedonometer dropped way down on the day of Michael Jackson’s death this summer. 🙁
>”Our method is only reasonable for large-scale texts, like what’s available on the Web,” Dodds says. “Any one sentence might not show much. There’s too much variability in individual expression.” But that’s the beauty of big data sets* and statistics.< — Source: PHYSorg.com
Here’s an observation by D&D really tickles my ribs: Happiness of blogs increased steadily from 2005 to 2009, exhibiting a striking rise and fall with blogger age and distance from the Earth’s equator. Figure 9 of their publication reveals a maximum happiness valence near my age (56 years), latitude (45 degrees North) and the day I normally blog (Sunday). Thus I think that StatsMadeEasy must be near the top of the blog pile for cheerfulness, particularly given my guiding principal to keep it simple and make it fun (KISMIF).**
Nevertheless, I am throwing in a wet blanket over this whole write-up by alerting you to a recent (8/1/09) Science News report about “When Humor Humiliates.” I now fear that being overtly happy, to the extent of laughing out loud (LOL), might provoke hard feelings from those who suffer from gelotophobia – fear of being laughed at. According to a survey of more than 20,000 people in 73 countries this phobia is widespread, but particularly active in certain cultures. The USA seems to fare well in specific aspects of gelotophobia – particularly the city of Cincinnati. So if you just cannot contain your belly laugh, let it all out there in the midsection of America. 😉
* These two enterprising professors report they examined nearly 10 million blog sentences!
** Search on “happiness” for my prior musings on statistics related to this subject.
Regions with aging populations are experiencing higher death rates!
Posted by mark in politics, Uncategorized on August 10, 2009
If the USA moves to government-sponsored health care on the scale of Europe, death rates here (now 8.3 per thousand) are sure to increase to the trans-Atlantic level of 10.3 — that’s a fear which Economist Edward Lotterman rebuts in his newspaper column today. As you educated readers might guess, the discrepancy in death rates can be easily explained by differing demographics: Due differing post-WWII dynamics, Europe’s population is older than ours, which can be seen in these animated population pyramids on Europe versus the United States developed by Professor Gerhard K. Heilig.
Specific statistics like this, when used indiscriminately by strongly-biased people, give statistics as a whole a bad name. However, those who are not duly diligent in vetting inflammatory stats are just as much to blame as the originators misleading them.
“It is proven that the celebration of birthdays is healthy. Statistics show that those people who celebrate the most birthdays become the oldest.” — Widely quoted as stemming from a PhD thesis by S. den Hartog (perhaps too good to be true!)