> Hm, I thought that the negative exponential distribution (which > governs the waiting time between events in a Poisson process -- > the Poisson distribution represents the counts in a given interval) > was "without memory" and so the distinction was unimportant? > Ie. you come to the bus stop and the bus is 15 minutes away on > average; you wait for five minutes with no bus, and it's _still_ > 15 minutes away on average :-)
I think rather memoryness (a condition I have as well ;-) ) says P(T > s + t | T > s) = P(T > t) for all s, t > 0. So after 5 minutes the probability it was 15 minutes from when you arrived (10 minutes from now) is the same as the probability it arrives within 10 minutes of when you first got there. So you have the memory, not the process. Should be able to check this with a quick change of variable in the Intergral--but I got to get to school... CC _______________________________________________ Prime mailing list [email protected] http://hogranch.com/mailman/listinfo/prime
