Group 3: Goh Jie Sheng/ Bok Wen Xuan/ Annabella Fong What a Coincidence Group 3: Goh Jie Sheng/ Bok Wen Xuan/ Annabella Fong

Sources The presentation is referenced from: Kolata, G. (1990) “1-in-a-trillion coincidence, you say? Not really.

Let me share a story I was walking to Kent Ridge I saw a friend with sunglasses same as mine I saw my professor, wearing the same sunglasses as well What a coincidence

Context for today Engaging activity The Law of very large numbers Multiple-End coincidences Close-but-not-exact coincidences Activity summary Conclusion

Do not let others see what you write Activity TIME Fill in your: Birthday 2) Your Favourite ice cream flavour 3) Your favourite MRT station Do not write your name. Do not let others see what you write

Law of very large numbers Devised by Dr Persi Diaconis and Dr Frederick Mosteller from Harvard Coincidences arise “all the time” and the key is that, which events are the luck of the draw. Also: “ With a large enough sample, any outrageous thing is apt to happen ”

Coincidences and science In many incidences of the luck of the draw. Odd things happen because of many reasons that happen in life 01 There are no extraordinary forces so superstition is out of context 02 Things happen for a reason. 03

Coincidences and science The parameters of chances have been decimated by conditions (workplace vs accidents, field of study vs career opportunities” The sample size changes in different places

Lottery and lucky stores (旺地 wang4 di4/ tempat bertuah) You might have came upon some uncle and aunties saying that certain SgPools stores being more “lucky” than other For example, like the store at Chinatown Point being “lucky” because a lot of Toto 1st price have been struck from tickets purchased there. But that’s not a coincidence that that place has 3 people hitting jackpot a month, buying from the same store

Bringing this context to USA For striking a certain from of 7 digit lottery, it is a 1 in 1,000,000 coincidental chance per day Since America has a populace of ~250million 250 coincidences a day? Not very coincidental. This is known as the blade-of-grass paradox

Analysing our Class Later… Pass me back your little pieces of information

Multiple-end Coincidences Occasions when what might qualify as a coincidence, is not spelled out ahead of time The truth is everything might be a coincidence, but yet not a coincidence.

Close-but-not-exact coincidences If happenings are not exact, but close, the chances are even higher (Same color animal?) This is because you create a larger sample size versus the original chance measurements A good discussion would be that of birthdays.

01 02 03 Let’s look at your info Birthdays? Ice cream flavors MRT likings 03

Back-up plan What about our attire for today? Color of our clothing Types of shoes Types of shirt Ah… and type of sunglasses. For sale maybe?

Coincidences can be seen as a compilation of flawed arguments. Ending off… Quoted from Dr Diaconis, No one story holds up on its own. But taken together, they mean something. If you put all these near coincidences together, doesn't it indicate that something strange is going on? Coincidences can be seen as a compilation of flawed arguments.

Thanks for being such great audience for these weeks. END Thanks for being such great audience for these weeks.