Jump to content
Sign in to follow this  
paganinio

Today's Birthday problem

Recommended Posts

on the homepage of SFN, I clearly see that we have 3121 members, but only 1 member's birthday is today.

of course there are many users that didn't enter their birthdays to their profiles, but this number is still very impossible.

could anyone give a mathemetical explanation?

Share this post


Link to post
Share on other sites

Two points:

  1. Clearly it is not impossible as it has happened.
  2. Please do not qualify an absolute. A thing is either impossible or it is possible. It is not very impossible, slightly impossible, etc.

Now I am going to count how many people have registered their birthdays.

Share this post


Link to post
Share on other sites

yeah, i agree with ophiolite... why is it impossible? esp. as it has happened!?

 

also, those who havent entered their birthday obviously will not appear on that list as no one will know their birthday!

 

now that was rocket science!

 

:D

Share this post


Link to post
Share on other sites

It's possible that on a forum where there are about 3000 members, all have birthdays in, let's say, February. As stated, it's just very unlikely, but possible.

Share this post


Link to post
Share on other sites

...No one complains when there are just two birthdays, so why bring it up when there's only one?

 

It's statistically odd, yes, and it'd be even more odd if we didn't have any birthdays at all, but easily possible.

Share this post


Link to post
Share on other sites

This thread is fairly pointless.

 

Hardly anyone puts their birthday information in to their profiles - that's the explanation. It's by no means a freaky phenomenon, or unique to SFN.

Share this post


Link to post
Share on other sites

"Hardly anyone puts their birthday information in to their profiles"

 

Yeah, that's just voluntarily making the FBI's work easier. :rolleyes:

Share this post


Link to post
Share on other sites

I never put my birthday in my profile simply because it isnt relevent but if anyone wants to use paypal to send me some money,let me know and i will give you the details my birthday is Dec19.

Share this post


Link to post
Share on other sites

"Hardly anyone puts their birthday information in to their profiles - that's the explanation."

 

actually if you chose any random month (i chose may 05 because its my birthday!)

http://www.scienceforums.net/forums/calendar.php?s=&c=1&week=&month=5&year=2005

then you will find quite a few birthdays per month. whilst relative to the member count there arent that many - if you take into account what sayo said (quoted above) there are still a lot of members who entered there birthdates. also if you look at the member list there are many who havent even ever posted!

subtract the once or twice time posters there no where near 3000 members. this will also contribute to the factor we're talking about!

Share this post


Link to post
Share on other sites

I gave up counting when I got to 25 members without declared birthdays 18 with. I think I did it for two starting letters. So, a significant proportion of members may have declared their birthdays.

 

Methinks, Sayonara was favouring Rene over Isaac!

Share this post


Link to post
Share on other sites

if you go to the member list and arrange everyone in least posts first on page 78 out of 90 there are still people who have only posted 10 times:

http://www.scienceforums.net/forums/memberlist.php?&order=asc&sort=posts&pp=30&page=78

 

these people who posts 10 times in their life are either brand new members or probably came for a few threads and then left. when you consider that 78/90 thats over 80% of that 3000 members have only posted 10 times then you realise why not everyone of those 3000+ members have their birthday. (because a few time posters dont normally fill out profiles).

 

infact if you take that into account quite a lot of members have filled out their profile (incl. birthday)

Share this post


Link to post
Share on other sites

Excellent point. Once again proves that if you work the data hard enough it can confirm your prejudices. In this case, since they are also my prejudices, they must be correct.

Share this post


Link to post
Share on other sites
In this case' date=' since they are also my prejudices, they must be correct.

[/quote']

ROFLOL

 

but on a serious note it is true! just look at the proof

Once again proves that if you work the data hard enough it can confirm your prejudices

Share this post


Link to post
Share on other sites

I don't really get you. sorry. what's your point? Asking about probabilitieS?

Share this post


Link to post
Share on other sites

If anyone is really interested we can get the total number of birthdays from the DB with a simple SQL query.

Share this post


Link to post
Share on other sites

fire away with the query, they dont take very long and it would put an end to the debate!

 

remember to take into account that over 80% of the members have posted less than 11 times, calssifying them as non-regular posters. these people are a lot less likely to fill in their DOB or even anything in their profile at all.... however the query will show all!

Share this post


Link to post
Share on other sites

yeah obviously but Im saying that the majority of the members are non-regular posters who are unlikely to have properly filled in (including personal data such as DOB) as they are non-regular posters.

 

This may make the result biased.

 

All the same.... run the query... it'd be interesting (as far as this thread is concerned with anyway!)

Share this post


Link to post
Share on other sites
yeah obviously but Im saying that the majority of the members are non-regular posters who are unlikely to have properly filled in (including personal data such as DOB) as they are non-regular posters.

Irrelevant.

 

 

This may make the result biased.

No it won't. It affects the explanation, not the results.

Share this post


Link to post
Share on other sites
No it won't. It affects the explanation, not the results.

 

it effects the explanation or analysis of the result.

 

in that if the result goes against what i have previously predicted the pattern to be... that will be the explanation from this alteration from my prediction.

 

basically i think that over 50% of the people would have inserted a DOB, if the query returns a result differing from that it is because over 80% of SFN members are non-regular posters...... etc etc

 

now can you please do the $#~*ing query because i really wanna know now!!!!! :D

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.