Recent content by ndrue

Thanks for your help. Now I understand why weibing's calculation works: (1/365)^2 * 4C2 * 364/365 * 363/365 is the probability that two people share the some specified birthday d, AND the other two birthdays are different. Because these events are disjoint for each d, we can multiply by...

Yes I know that, but my question was why that calculation is wrong when it appears to follow the same logic of another, correct calculation. Perhaps this would be a better question: what is the probability that at least one cell has exactly 2 balls (people)? For N people, would this not be...

Suppose we wanted to calculate the probability that at least 2 people share a birthday with someone else. So we don't care about the birthdays of the others. By the weibing's method, wouldn't this be given by 365/365 * 4C2 * 365/365 * 365/365 ? This clearly isn't right since adding the...

If the density is _defined_ as a Radon-Nikodym derivative, then (1) is basically the statement of the Radon-Nikodym theorem, in which case it is true by definition. Then (2) becomes a proof that the density is equal to the derivative of the distribution function.

How exactly is this a weird request? I just want the weights of a minimum spanning tree. Anyway I've found a way around this: to get the weighted adjacency matrix of the MST, I just took the pointwise (Hadamard) product of the unweighted matrix with the original matrix of weights.

Hi, really sorry for the bump, I'm having the same problem. Any help would be greatly appreciated.