From 25f24b01e3b675c6afbb653f07034a3c9a6aee32 Mon Sep 17 00:00:00 2001 From: Raymond Hettinger Date: Wed, 12 Mar 2025 13:25:31 -0500 Subject: [PATCH] Improve docstring for random.binomialvariate (gh-131164) Add probability distribution to the docstring --- Lib/random.py | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/Lib/random.py b/Lib/random.py index 1abcae77c8be..4d9a047b0279 100644 --- a/Lib/random.py +++ b/Lib/random.py @@ -792,12 +792,18 @@ class Random(_random.Random): sum(random() < p for i in range(n)) - Returns an integer in the range: 0 <= X <= n + Returns an integer in the range: + + 0 <= X <= n + + The integer is chosen with the probability: + + P(X == k) = math.comb(n, k) * p ** k * (1 - p) ** (n - k) The mean (expected value) and variance of the random variable are: E[X] = n * p - Var[x] = n * p * (1 - p) + Var[X] = n * p * (1 - p) """ # Error check inputs and handle edge cases -- 2.47.3