sars said:
Bumpy, I'm going to disagree with fallingman and say you are quite special in that you and your car share the same day and month of a birth.
His approach was to simply divide the number of members by 365 giving 24 or so, 365 is used because you were born on only one day so 1/365. However I do not believe that he/she has taken into account the cars birthday and thus you have to combine the two , such that it becomes 1/365 x 1/365 x no of members, equates to a probability of 1 in 133,225 members.
This means you are going to be the only one or probability is just probability or I'm a complete arse and wrong
I never wanted to imply Bumpy wasn't special - let's face it, we're all pretty special on here!
But I do want to disagree with your maths. Take just one member, for example myself... What is the chance that I share a birthday with my car? Well, first let's look at the car's birthday, which is fixed, and say "What are the chances I have the same birthday?" Well the car could only have been born on one of 365 calendar days so there is a 1/365 chance I was born on the same date. Or you can do it the other way round, take my birthday as the fixed point, and say the car has a 1/365 chance of sharing it. You don't need to come at it from both directions at the same time to make 1/365 x 1/365, because as soon as you start with the car (or me), you start with a fixed date.
Think of it this way, let's say your birthday is 23rd March. We'd know that for a fact, so the chance that your birthday is 23rd March is 1/1. Then it's just a 1/365 chance your car is the same.
If you don't know either of them in advance, the chances that a member and their car were both born on a specific day, say the 17th June, is 1/365 x 1/365. But if we don't care what the day is, just that they have the same day as each other, then you can get rid of one of those 1/365s.
And I'm not saying you're "a complete arse", either! Statistics and probability are a slippery business - and I'm a self-confessed spoddy geek. Sorry! Also I admit there's a probability that I've got it wrong too!
By the way, all of this ignores Leap Years and assumes that BMW manufactures Z4s evenly across the year.
Finally, is it possible to set up a poll to find out how many of us do share their Z4's birthday - I for one don't.
