[commons-math] branch master updated: MATH-1644: Prevent computed probability from exceeding 1.

[erans]

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erans pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-math.git


The following commit(s) were added to refs/heads/master by this push:
     new f067b2b4b MATH-1644: Prevent computed probability from exceeding 1.
f067b2b4b is described below

commit f067b2b4bae9d7690a84cd65bedd45bca5691441
Author: Gilles Sadowski <gillese...@gmail.com>
AuthorDate: Sat Apr 9 14:07:03 2022 +0200

    MATH-1644: Prevent computed probability from exceeding 1.
---
 .../apache/commons/math4/legacy/stat/inference/BinomialTest.java   | 2 +-
 .../commons/math4/legacy/stat/inference/BinomialTestTest.java      | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git 
a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/stat/inference/BinomialTest.java
 
b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/stat/inference/BinomialTest.java
index 80650c9b4..a7deb3187 100644
--- 
a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/stat/inference/BinomialTest.java
+++ 
b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/stat/inference/BinomialTest.java
@@ -138,7 +138,7 @@ public class BinomialTest {
                     if (criticalValueLow == criticalValueHigh) {
                         pTotal += pLow;
                     } else {
-                        pTotal += 2 * pLow;
+                        pTotal += 2 * Math.nextDown(pLow);
                     }
                     criticalValueLow++;
                     criticalValueHigh--;
diff --git 
a/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/stat/inference/BinomialTestTest.java
 
b/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/stat/inference/BinomialTestTest.java
index bf83dfa17..f480e0b66 100644
--- 
a/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/stat/inference/BinomialTestTest.java
+++ 
b/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/stat/inference/BinomialTestTest.java
@@ -126,4 +126,11 @@ public class BinomialTestTest {
         Assert.assertFalse(testStatistic.binomialTest(trials, successes, 
probability, AlternativeHypothesis.GREATER_THAN, alpha01));
         Assert.assertFalse(testStatistic.binomialTest(trials, successes, 
probability, AlternativeHypothesis.LESS_THAN, alpha05));
     }
+
+    @Test
+    public void testMath1644() {
+        final BinomialTest bt = new BinomialTest();
+        final double pval = bt.binomialTest(10, 5, 0.5, 
AlternativeHypothesis.TWO_SIDED);
+        Assert.assertTrue("pval=" + pval, pval <= 1);
+    }
 }