On Nov 14, 2014, at 10:54 AM, Viktor Dukhovni wrote: > On Fri, Nov 14, 2014 at 10:26:29AM -0600, Edgar Pettijohn wrote: > >>> On January 15th each year Wietse sets a counter for the following >>> year's release to zero. Each day after that he rolls a 6 sided >>> dice, and adds the value to the running total. When the total >>> reaches 1278, a new release is cut. :-) >> >> So around August? > > [ Off topic alert, move along... ] > > Your arithmetic is different than mine. > > $ echo "2k 1278 3.5 / p" | dc > 365.14 > > Your task is to compute the variance, it is easy to compute the > variance of total after 365 days. I have not thought about how to > correctly compute the variance of the number of days needed to > reach a target total. A naive order of magnitude guess is to take > the variance of the expected total after 365 days and divice by > the mean increment per day. That gives a guestimated standard > deviation of ~sqrt(365 * 35/12)/3.5 or 9.5 days. Replace the dice > with a coin toss, how does that change the standard deviation? :-) > > -- > Viktor. >
It would be a minimum of 213 days which is around august or a maximum of 3 1/2 years which would be around august. Plus there are probably unwritten rules. For all we know he re-rolls all 3's.
