[Python-checkins] cpython: Add cum_weights example (simulation of a cumulative binomial distribution).

[raymond.hettinger]

https://hg.python.org/cpython/rev/73ed94ebdbbc
changeset:   104579:73ed94ebdbbc
user:        Raymond Hettinger <python at rcn.com>
date:        Thu Oct 20 01:36:52 2016 -0700
summary:
  Add cum_weights example (simulation of a cumulative binomial distribution).

files:
  Doc/library/random.rst |  7 +++++++
  1 files changed, 7 insertions(+), 0 deletions(-)


diff --git a/Doc/library/random.rst b/Doc/library/random.rst
--- a/Doc/library/random.rst
+++ b/Doc/library/random.rst
@@ -351,6 +351,13 @@
    >>> choices(['red', 'black', 'green'], [18, 18, 2], k=6)
    ['red', 'green', 'black', 'black', 'red', 'black']
 
+   # Probability of getting 5 or more heads from 7 spins of a biased coin
+   # that settles on heads 60% of the time.
+   >>> n = 10000
+   >>> cw = [0.60, 1.00]
+   >>> sum(choices('HT', cum_weights=cw, k=7).count('H') >= 5 for i in range(n)) / n
+   0.4169
+
 Example of `statistical bootstrapping
 <https://en.wikipedia.org/wiki/Bootstrapping_(statistics)>`_ using resampling
 with replacement to estimate a confidence interval for the mean of a small

-- 
Repository URL: https://hg.python.org/cpython