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https://issues.apache.org/jira/browse/MATH-1644?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Gilles Sadowski resolved MATH-1644.
-----------------------------------
Fix Version/s: 4.0
Resolution: Fixed
Patch applied in commit f067b2b4bae9d7690a84cd65bedd45bca5691441 ("master"
branch).
> BinomialTest returns p-values > 1
> ---------------------------------
>
> Key: MATH-1644
> URL: https://issues.apache.org/jira/browse/MATH-1644
> Project: Commons Math
> Issue Type: Bug
> Affects Versions: 3.6.1
> Reporter: Chad Young
> Priority: Minor
> Fix For: 4.0
>
> Attachments: patch
>
>
>
> The code below produces the output "P-value for 10 trials, 5 successes,
> probability 0.5, two-sided alternative is 1.2460937500000002", but p-values
> should never be greater than 1. I think what is happening is that the test is
> adding both one-sided alternatives, but both include the 5 successes
> probability, so it is counted twice. This happens whenever the number of
> successes is exactly what is expected based on number of trials and success
> probability (numberOfSuccesses = numberOfTrials * probability).
> {code:java}
> import org.apache.commons.math3.stat.inference.*;
> public class Main {
> public static void main(String args[]) {
> BinomialTest bt = new BinomialTest();
> Double pval = bt.binomialTest(10, 5, 0.5,
> AlternativeHypothesis.TWO_SIDED);
> System.out.println("P-value for 10 trials, 5 successes, probability
> 0.5, two-sided alternative is " + pval);
> }
> }
> {code}
>
>
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