3 ms·
If rocket failures were a Poisson process with a low rate, you'd expect to see some clustering by random chance. And if they're being watched by the media, you
by pjscott 10y ago
If rocket failures were a Poisson process with a low rate, you'd expect to see some clustering by random chance. And if they're being watched by the media, you should expect to see people making much of it, whether or not there's a systemic problem.
As with most news, I recommend waiting a decade and buying a history book.
- dkbrk 10y agoYour assertion that there would be "some clustering by random chance" is correct, however rocket failures are most definitely not described well by a Poisson distribution. The simplest reasonable model would be to assume each launch campaign has a fixed probability of failure, and that the probability of any given failure event is independent of the others. In other words, a binomial distribution. And this is a commonly applied model, I've seen a number of people doing such calculations in the last few days. However, these assumptions do not accurately reflect reality. When a failure occurs launches are stopped, the problem is identified, and the problem is fixed. A failure event should cause reliability to increase for subsequent launches; failures are not conditionally independent.