Comments on: Are birthdays evenly distributed across the year? * http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/ pieces of my mind splattered over the internet Thu, 29 Oct 2009 03:45:47 +0000 http://wordpress.com/ hourly 1 By: Ranbo http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-678 Ranbo Mon, 18 May 2009 17:36:13 +0000 http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-678 I have friends from Somalia who simply do not know their birthdates (although they do know what day of the week each was born). So they put "January 1" on all forms as their birthday. So I wasn't surprised at all to see that spike in January--it simply reflects a lack of knowledge of that date. I was curious about a daily birth rate chart, to see if things like Valentine's Day had a corresponding spike distributed 9 months later. I have friends from Somalia who simply do not know their birthdates (although they do know what day of the week each was born). So they put “January 1″ on all forms as their birthday. So I wasn’t surprised at all to see that spike in January–it simply reflects a lack of knowledge of that date.

I was curious about a daily birth rate chart, to see if things like Valentine’s Day had a corresponding spike distributed 9 months later.

]]> By: mynah http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-669 mynah Sun, 13 Jul 2008 02:27:20 +0000 http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-669 I live in the Southern hemisphere, and noticed a peak in birthdays in June and July, which ties in nicely with the increase (even if corrections are done for assigned birthdays) in December and January in the Middle East. I live in the Southern hemisphere, and noticed a peak in birthdays in June and July, which ties in nicely with the increase (even if corrections are done for assigned birthdays) in December and January in the Middle East.

]]> By: Are more people born during specific times of the year? - Science Forums http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-668 Are more people born during specific times of the year? - Science Forums Sun, 13 Jul 2008 01:29:13 +0000 http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-668 [...] something wrong with the dataset, or May is the most romantic time of year in the Middle-East ! Are birthdays evenly distributed across the year? * Realm Of Randomness __________________ Come warm yourself beside the fire and hear of days of [...] [...] something wrong with the dataset, or May is the most romantic time of year in the Middle-East ! Are birthdays evenly distributed across the year? * Realm Of Randomness __________________ Come warm yourself beside the fire and hear of days of [...]

]]> By: Randomizer http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-481 Randomizer Mon, 17 Dec 2007 02:31:21 +0000 http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-481 Nice article, that ! No doubt he'll be able to statistically show that astrology is indeed bull ... that was a really simple and smart way to go about doing it. :) Nice article, that ! No doubt he’ll be able to statistically show that astrology is indeed bull … that was a really simple and smart way to go about doing it. :)

]]> By: Luciferratic http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-473 Luciferratic Thu, 13 Dec 2007 07:02:18 +0000 http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-473 Looks like everyone is talking about B'days and their distribution. Have a look at this recent article at Freakonomics http://freakonomics.blogs.nytimes.com/2007/12/12/whats-the-significance-of-your-sign-a-guest-post/#more-2152 Looks like everyone is talking about B’days and their distribution. Have a look at this recent article at Freakonomics

http://freakonomics.blogs.nytimes.com/2007/12/12/whats-the-significance-of-your-sign-a-guest-post/#more-2152

]]> By: Randomizer http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-470 Randomizer Wed, 12 Dec 2007 13:25:30 +0000 http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-470 @Luciferratic - Appended the new info learnt - I must say, this is a great brain-teaser :) @Luciferratic – Appended the new info learnt – I must say, this is a great brain-teaser :)

]]> By: Randomizer http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-468 Randomizer Tue, 11 Dec 2007 13:27:57 +0000 http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-468 @Luciferratic - That's amazing, right ? :) ... A trivial exercise such as this one and we ended up learning about the census system in the Middle East in the 1950's ! I would have never thought of that, no matter how much I brainstormed. I shall revise the data, and no, there's no need for any abstaining of any sort ! :) @Luciferratic – That’s amazing, right ? :) … A trivial exercise such as this one and we ended up learning about the census system in the Middle East in the 1950’s ! I would have never thought of that, no matter how much I brainstormed.

I shall revise the data, and no, there’s no need for any abstaining of any sort ! :)

]]> By: Luciferratic http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-467 Luciferratic Tue, 11 Dec 2007 08:21:03 +0000 http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-467 Randomizer - I have to agree with you, there definitely is something wrong as the birth rates cannot be skewed to this extent and I have been asking around. This is the first time anyone has tried to look at the portfolio on the basis of month of birth as it really has no relation to the risk profile of a customer. So, I asked around as to possible reasons as to why the data could be so skewed. Apparently the data is correct, its the birth DATES that are wrong. And I DO apologize about this as I should have checked before posting such a reckless response. The country I reside in has had a national identification system in place only since 1950. Prior to that there was no official document used to identify birth dates! When the National ID came into play in 1950 most people didn't know which month they were born in and they were randomly assigned dates in January more often than not the 1st of January! Yes I know it sounds stupid, but prior to 1950, people here were familiar with the Islamic Calendar (Hijri Calendar) and were not used to the Gregorian Calendar. A market norm is to use the date of birth as appearing on the National ID and the result as you have already seen is the data is skewed towards January for customers that were born before 1950. I apologize to you and to all of your readers for such a big mistake on my part. I also apologize to Sharath as I know he's posted the same data on his blog as well. I ran the data again, but this time excluded anyone that was born prior to 1950 and while I understand all of your skepticism, the previous findings still hold, but with a far more reasonable spike in December and January. The revised findings are as follows: Jan> 10.94% Feb> 8.00% Mar> 8.31% Apr> 7.44% May> 6.74% Jun> 6.99% Jul> 7.89% Aug> 8.89% Sep> 7.96% Oct> 8.46% Nov> 8.49% Dec> 9.89% Once again, I do apologize for the goof up and I'm going to abstain from the blog world for a while - until all of you forget me and what I did. Randomizer – I have to agree with you, there definitely is something wrong as the birth rates cannot be skewed to this extent and I have been asking around. This is the first time anyone has tried to look at the portfolio on the basis of month of birth as it really has no relation to the risk profile of a customer.

So, I asked around as to possible reasons as to why the data could be so skewed. Apparently the data is correct, its the birth DATES that are wrong. And I DO apologize about this as I should have checked before posting such a reckless response.

The country I reside in has had a national identification system in place only since 1950. Prior to that there was no official document used to identify birth dates! When the National ID came into play in 1950 most people didn’t know which month they were born in and they were randomly assigned dates in January more often than not the 1st of January! Yes I know it sounds stupid, but prior to 1950, people here were familiar with the Islamic Calendar (Hijri Calendar) and were not used to the Gregorian Calendar. A market norm is to use the date of birth as appearing on the National ID and the result as you have already seen is the data is skewed towards January for customers that were born before 1950.

I apologize to you and to all of your readers for such a big mistake on my part. I also apologize to Sharath as I know he’s posted the same data on his blog as well.

I ran the data again, but this time excluded anyone that was born prior to 1950 and while I understand all of your skepticism, the previous findings still hold, but with a far more reasonable spike in December and January.

The revised findings are as follows:

Jan> 10.94%
Feb> 8.00%
Mar> 8.31%
Apr> 7.44%
May> 6.74%
Jun> 6.99%
Jul> 7.89%
Aug> 8.89%
Sep> 7.96%
Oct> 8.46%
Nov> 8.49%
Dec> 9.89%

Once again, I do apologize for the goof up and I’m going to abstain from the blog world for a while – until all of you forget me and what I did.

]]> By: Birthday distribution - Middle-east edition « Epistles http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-466 Birthday distribution - Middle-east edition « Epistles Tue, 11 Dec 2007 02:56:33 +0000 http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-466 [...] December 10, 2007 Posted by Sharath Rao in statistics. trackback Luciferratic, a commenter on therandomizer’s  blog ( am seriously getting pissed with these pseudonames ) has access to a much larger dataset [...] [...] December 10, 2007 Posted by Sharath Rao in statistics. trackback Luciferratic, a commenter on therandomizer’s  blog ( am seriously getting pissed with these pseudonames ) has access to a much larger dataset [...]

]]> By: Randomizer http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-463 Randomizer Tue, 11 Dec 2007 00:20:10 +0000 http://therandomizer.wordpress.com/2007/12/08/are-birthdays-evenly-distributed-across-the-year/#comment-463 @Caffeinator : I'm still an official grad student, till this Friday :). So it's all fair game. @Sallu : Fund me man ! :) Anyways, the pounds are kicking the dollar's arse - so it won't cost you much ! ;) @Caffeinator : I’m still an official grad student, till this Friday :). So it’s all fair game.

@Sallu : Fund me man ! :) Anyways, the pounds are kicking the dollar’s arse – so it won’t cost you much ! ;)

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