<p>I was born on November 23rd. I’ve never really thought about the date of my conception, to tell you the truth.</p>
<p>One in 365.25 people share your birthday.</p>
<p>So if your school has 2000 people, 4 other people have your birthday.</p>
<p>For November 18th or 23rd?</p>
<p>I never though of it this way, another funny concept. So if one in 365.25 kids share my birthday, then it must be a stroke of luck that there 6 kids with the same birthday as I, and my school population is only 300!</p>
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It’s for any birthday. [How</a> Many Share Your Birthday](<a href=“http://geography.about.com/od/lists/a/sharebirthday.htm]How”>Find out How Many People Were Born on Your Birthday)</p>
<p>^ That’s false. If you had an equal chance of being born on all days then we could reasonably assume that. However, you do not have an equal chance of being born on all days. Which is proven by September having much more births than any other month.</p>
<p>Plus, think about the disproportional number of people born on Feb 29th than any other date.</p>
<p>Actually, there is an equal chance of being born on all days. It just doesn’t happen that an equal number of people are born on each day.</p>
<p>Just because there happen to be more births in September doesn’t mean there is a greater chance of being born in September. It’s all based on sexual activity, really.</p>
<p>And the fertility of people,
and you don’t always get preggo first sexual experience.</p>
<p>It’s reasonable to say I was conceived in October as I was born in July</p>
<p>HAHA… Yeah, November 18 is an awesome song by Drake.</p>
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I don’t think this makes sense. Don’t probabilities change with the amount of information you have about a system?</p>
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Lol, really? I rather suspect I’m a mistake as well. I recall my mother saying that I was ‘A surprise’, although I had no idea what she was talking about at the time. Birthday in late September so, Christmas/New Years. :/</p>
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<p>??? Huh? Probabilities do not change based on evidence. The theoretical probability of having a birthday is equal for every day of the year. There is nothing special about any day that causes more births on that particular day. However, the EXPERIMENTAL probability (what actually happens) isn’t always the same as the theoretical probability, as is the case with birthdays. There happen to be more August/September and November birthdays because of sexual activities nine months prior, during Hanukkah/Christmas, New Years, and Valentine’s day. If people didn’t tend to have sex on special occasions, and the frequency of sex was perfectly even throughout the year (same number of conceptions per day/night), then the number of births would be about even for every day of the year. Since we don’t live in such a utopian situation, such is not the case.</p>
<p>
Suppose a person has two children </p>
<p>Let E -> Event that both are males
P(E)=1/4</p>
<p>If you know that one child is a male:
P(E)=1/3</p>
<p>If you know that the elder child is a male:
P(E)=1/2</p>
<p>Clearly the probabilities change based on available evidence.</p>
<p>The theoretical probability of having a birthday is equal for every day of the year. This is only the case if we assume that “the frequency of sex was perfectly even throughout the year.” This is clearly a wrong assumption, so why make it?</p>
<p>I do want to question that probability and ask is this at ideal conditions? Because I’m fairly certain nothing in conception and fertility is ideal and alters this probability.</p>
<p>Why does this even matter? People have sex when they want to have sex, when someone is pregnant, it’s either an accident or planned…</p>