Realm Of Randomness

December 8, 2007

Are birthdays evenly distributed across the year? *

Filed under: Academic,Freakonomics,Musing — Randomizer @ 12:46 am

[* Two updates appended at the bottom]

It started off as a wasteful exercise by Sharath, where he tracked birthdays for two weeks on Orkut just to see if he knew at least one person born on each day of the year. Something I noticed from his sampling though, was that he had about 2 birthdays / day in his stats … which means he should have roughly 365×2 = 730 friends on his Orkut list. Well, guess what, he has 736 friends on his list! Which suggested that birthdays are sort of evenly distributed across the year.

However, in my personal observation, I’ve seen more people born in the latter half of the year, than the first half. There always seemed to be a ton of birthdays around Oct/Nov rather than, say, April/May. He then went on to make a distribution of birthdays from his class of ’97 – and found that there were 28 birthdays in the first half as opposed to 36 in the second – a small victory for my observation. I couldn’t wait to try this on more stats, so I sampled my own class of ’98 – fairly simple, as we have a database on our yahoo group, and these were the results:


The stats for my class are: 34 born in the first half, and 33 born in the second half – an almost even distribution. Well, so much for my lead :( . But I found an interesting article on the monthly distribution of births in rural India – and guess what ? There is a very clear bias for births in the second half. Which means – high rates of conception in December/January. The paper also refers to a similar increase in conception rates in the United States, attributed to the Christmas (Holiday?) season :) .

So what are the factors you think contribute to an uneven distribution ? Off the top of my head – I’d say

  • Astrological ‘luck’ periods – especially for couples in India
  • Admission to Kindergarten – I’d assume that more people would like their kids to *just make* the eligibility criteria. For instance, if the cut-off for admission to Kindergarten is ‘Those born in 95’, I’d think that people would think it is an advantage to be born in the latter half of ’95, say Nov-Dec, as they are almost a year younger than those born in Jan, yet they are on the same ‘level’ academically.
  • When you get married also influences birth – at least it used to :) .

What are the other reasons you think there are for an uneven distribution of births across a year? Have you noticed a trend amongst your friends?

On another note, I can probably explain why I *feel* more of my friends are born in the latter half of the year – It is simply because I’m born in October and it is more easy for me to remember those that were born in Sep/Oct/Nov than in the earlier half of the year :). I’m not sure what bias to call it. Maybe you can help me with that too.

Update 1: A regular visitor and commentator at this site, Luciferratic gives us some data from a much larger dataset. The chart is astonishing. There is either something wrong with the dataset, or May is the most romantic time of year in the Middle-East ! :)


Update 2: Our instincts are right … there is a reason there are that many January-borns in the data set … Wanna brainstorm on this for a while ? So what you know as of now is : The dataset is huge, it has data of people of all ages, and they are mostly middle-eastern. Now: What possible reason can you think of for this spike in the dataset for January?

Spend some time on this… the solution is elusive but I’m sure someone should be able to figure this out!





Luciferratic answers this question (along with a bunch of unnecessary apologies!) in his comment here.

Taking January out of the graph, as we know it is likely to have skewed data, the graph is quite even, as follows. There still seems to a bias towards the latter half though (Note: I have not corrected the percentage values in the graph, merely removed the January bar):



November 12, 2007

Adaptation and the American dream

Filed under: Introspection,Milestone,Musing,Personal — Randomizer @ 3:58 am


The last month has been great, busy with so many milestones – turning 25, moving to a new city, and getting my first pay-cheque :). After the much awaited internet service was set up at my place, it seems like I can finally get back to making some changes in my online world as well ! 

Moving to Houston was pretty exciting, as for the first time in my life, I am living completely on my own. I had rooommates or family at all points in my life, and it was great to turn 25, while holding the keys to an apartment and a car in the much sought after US of A – something that I never dreamt for myself when I was growing up in the 90’s.  It is amazing how quickly my life changed – not too long ago, I was sharing a really tiny room in Bangalore with 2 other people, hand-washing my clothes on Sunday morning, and owning the rights to only 1/3rd of the space in the common Godrej wardrobe.

Thinking about the shift fascinates me in so many ways, on so many different levels… For one thing, the exact same person is viewed and valued so differently from one nation to the next. It’s like you are valued at $x when you got on the plane in Mumbai, but when you got off in New York, you and your profession were suddenly valued at 10 times $x, though nothing about you changed on the flight…  At the same time, someone else on the flight might have lost a lot from that flight – like maybe the European man who found himself valued by the Indian hospitality industry at 50 times his value during his vacation there!

I guess this is exactly what trade and business is all about – except that in this case, you yourself are the product in question.

Another interesting thing about the shift is – that one event, making the move from one shore to the other – resulted in such a different life. I can so easily picture an alternate reality in which I am still working and living in Bangalore, and pretty happy with it as well. So that brings us to another question… how many other events just like this are out there, that we are missing every day as the result of (a)resistance to change (b) ignorance (c) or the desire to try and be happy with what we have?

Finally, things like these remind you of all the places/environments/situations where you functioned, succesfully and perhaps happily… and gives you a sense of invincibility – that your environment will just absorb you into its system, wherever you go, and keep you comfortable.

We are all chameleons that way.

August 25, 2007

Home stretch

Filed under: Musing,Personal — Randomizer @ 3:14 pm


(img from CSU)

It’s been a marathon, alright ! But finally I can see the finish line … in the form of my defense on Aug 28th. But what I’m enjoying the most right now is this bursting feeling of excitement , the feeling of ‘I just can’t wait till ___’ .

One of the best parts about academic life is that we arrive at such moments every semester, or in the case of school, every year. Right in the middle of your final exams, studying for some painful subject like social studies or software engineering, your mind would take you through every damn thing you ever wanted to do in life, imagining you’d do it in that vacation immediately following that exam. Of course, whether or not you’d do it, or just laze around doing nothing is a different story altogether, but the dreams are rich and vivid nevertheless…

Back in the day, I used to plan how exactly I’d celebrate that first day of freedom – Ridding my room of every piece of visible study material, tearing up exam sheets, and just being overjoyed for the heck of it. In undergrad, my friends made the agony even more painful by having countdowns starting as long as 40-50 days in advance ! ‘This day next month we’ll be free’ !

I’ve been thinking that this is one of the last times I’m going to have that feeling, at least for a while, of bursting excitement, of endless days of fun hanging just beyond your grasp. My list of things to do, places to visit, people to meet, games to play, movies to watch and food to eat is growing rapidly. It’s funny how the ‘home stretch’ takes a literal form here because beyond the finish line actually lies a trip back home, hopefully for a month of fun and relaxation :)

I just can’t wait.

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