TITLE: Calculating probabilities over different time intervals
QUESTION [9 upvotes]: If there was a 10% chance of an event occurring over a year, how would I work out how likely this event is to happen per month, per day etc?
Now because if, using per month as an example, if it occurs in January it cannot happen again for that particular instance, which takes away simple division.

REPLY [4 votes]: Well, I think I have the answer to the ORIGINAL question. 
y=1−(1−x)^(1/365)
For odds on any given day
y=1−(1−x)^(1/12)
For odds on any given months, (assuming months are all the same length...)
Edit.
Incidentally, if it happens in January it doesn't mean it WOULDN'T have happened in February. This doesn't find the most likely day it happens. December doesn't become practically never, just because it likely happened already in January, (or February, or March).