Library · Short Excursions · Probability

Running Total of a Die

Roll a fair six-sided die until the running total first exceeds 12. What is the most likely final total?

Revised PDF handout Report an error

Two approaches. Monte Carlo gives 13 at roughly 28%. The analytic approach uses integer partitions: the number of ways to reach each total with parts ≤6\leq 6 and penultimate sum ≤12\leq 12. Comparing p(13,6)p(13,6) to ∑i=812p(i,6)\sum_{i=8}^{12} p(i,6) shows Pr⁡[13]≈28%\Pr[13] \approx 28\% exceeds Pr⁡[14]≈24%\Pr[14] \approx 24\%. Full code in the PDF.

Report an error on this page

Reports are stored by Netlify. See the privacy note.