The impact of a 100 meter asteroid could kill many people if it struck a major city. Suppose the probability of such an impact in any single year is 1 in 1,000, and suppose we know (somehow)that it has been 1200 years since the last impact. What would that tell us?
A)Nothing, we would still presume that the chance of such an impact during the next year is 1 in 1000.
B)The prediction must be wrong, since the time since the last impact has been 1200 years.
C)We are overdue for such an impact, so we should expect to be hit by something even larger during the next few years.
D)We are now due for such an impact, so the actual probability for the coming year must be much higher than 1 in 1000.

Question

Quizplus · Accepted Answer

The probability of a 100 meter asteroid impact in any single year is still 1 in 1000, regardless of how much time has elapsed since the last impact. The past does not affect the probability of future impact events.

The Impact of a 100 Meter Asteroid Could Kill Many