Recent content by DeDunc

Thanks Guys. Your contributions have been very helpful. As Vanadium suggests, it does look like a martingale.

Thanks DH But he says he is willing to make a bet to show that most stats professors will define/interpret the puzzle in the way that he has. From discussions on here, would you not say I would have more than evens chance of winning

So DH are you saying, if I take up the bet with him. a) I would expect to win if I call him on his maths- as the only answer- even in this restricted sense is 0.5 b) I would expect to win if I call him on his interpretation of the problem. He is offering a quite substantial bet on...

Which of the three things you mentioned above, is the most problematic?

Thanks to all contributors. I think the consensus is that the maths is right, but the interpretation is wrong and perhaps more worryingly, the interpretation has been tweaked to fit the maths. Just looking at the link Vanadium posted Landsburg says: Let’s say we ignore second generations...

Given what you have said above. Is Landsburg interpretation of the question reasonable? Ie could the average number of girls per simulation run be reasonably said to represent the fraction of girls in the population with this stopping rule.

I understand that he has calculated the expected fraction of girls per family, but I’m not clear exactly why this does not answer the question. Is it because with low numbers of children i.e. small numbers of families, the expected fraction of girls per family is biased against the contribution...

Micromass- yes "what fraction of the pollution are female is how it phrased". It was changed to female births to reflect the fact that most discussions of this problem, seem to ignore the mothers- who of course, are female. DH- Why is Landsburg wrong? Can you put your finger on which part of...

There’s a google interview question that’s been discussed quite a bit in various forums recently. The question is: There is a certain country where everybody has to have a son. Therefore each couple keeps having children until they have a boy, then they stop. In expectation, what fraction...

Oh great. Thanks HallofIvy & Sourabh. Both posted very useful replies just before I sent my last reply. HallsofIVy- I understand how the plane going through the centre intersecting the curve defines the great circle. But I couldn't see how this defines a shorter path I think Sourabh has...

At the risk of hi-jacking this thread can I ask the question in a different way. I fully expect that the question reveals a misunderstanding of geodesics so would be happy if someone could correct my thinking. Question below: If we imagine the surface of sphere (2-d) and draw a line of...

Thanks pervect, phyzguy and Brian. Your contributions have been very helpful to me. Pervect your comment highlights what it probably the misunderstanding underlying my question. I perfectly accept your calculation of your distance going around the latitude line is given by 1.414pi*r. In...

Thanks Ben for the reply. Very useful. I made a mistake with theta. It should be pi/4 all the way, well spotted. Another way to rephrase the question would be : If the line of latitude ( on the 2-d Sphere) I described is not a geodesic. How can I intuitively understand the geodesic that...

Simple question about geodesics. I have a question which I guess will be easy to answer for anyone who is familiar with the geometry involved in GR. Firstly, I have a numbered list which shows my (current) understanding of geodesics. If there is any wrong with my understanding please let...