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| author | Raymond Hettinger <rhettinger@users.noreply.github.com> | 2019-03-14 02:25:26 -0700 |
|---|---|---|
| committer | Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> | 2019-03-14 02:25:26 -0700 |
| commit | 41f0b78cbf204649bbae71662a115425c58f048d (patch) | |
| tree | 5d8c44ce22351b41e774d99c4e7c9b15f3be06d3 | |
| parent | 3191391515824fa7f3c573d807f1034c6a28fab3 (diff) | |
| download | cpython-git-41f0b78cbf204649bbae71662a115425c58f048d.tar.gz | |
Simplify overlap() formula for case where variances are equal (GH-12323)
| -rw-r--r-- | Lib/statistics.py | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/Lib/statistics.py b/Lib/statistics.py index 97f154373d..8d79eed6b1 100644 --- a/Lib/statistics.py +++ b/Lib/statistics.py @@ -773,7 +773,7 @@ class NormalDist: dv = Y_var - X_var dm = fabs(Y.mu - X.mu) if not dv: - return 2.0 * NormalDist(dm, 2.0 * X.sigma).cdf(0) + return 1.0 - erf(dm / (2.0 * X.sigma * sqrt(2.0))) a = X.mu * Y_var - Y.mu * X_var b = X.sigma * Y.sigma * sqrt(dm**2.0 + dv * log(Y_var / X_var)) x1 = (a + b) / dv |