diff --git a/src/main/java/org/apache/commons/math4/stat/inference/WilcoxonSignedRankTest.java b/src/main/java/org/apache/commons/math4/stat/inference/WilcoxonSignedRankTest.java
index efa9ca57b7..ee06866a56 100644
--- a/src/main/java/org/apache/commons/math4/stat/inference/WilcoxonSignedRankTest.java
+++ b/src/main/java/org/apache/commons/math4/stat/inference/WilcoxonSignedRankTest.java
@@ -288,8 +288,8 @@ private double calculateAsymptoticPValue(final double Wmin, final int N) {
      *            if true and x.length < 30, this is ignored because
      *            calculations may take too long)
      * @return p-value
-     * @throws NullArgumentException if {@code x} or {@code y} are {@code null}.
-     * @throws NoDataException if {@code x} or {@code y} are zero-length.
+     * @throws NullArgumentException if {@code x} or {@code y} is {@code null}.
+     * @throws NoDataException if {@code x} or {@code y} is zero-length.
      * @throws DimensionMismatchException if {@code x} and {@code y} do not
      * have the same length.
      * @throws NumberIsTooLargeException if {@code exactPValue} is {@code true}