diff --git a/src/main/java/org/apache/commons/math3/stat/inference/ChiSquareTest.java b/src/main/java/org/apache/commons/math3/stat/inference/ChiSquareTest.java
index cdcf5a2e5..885afb1ee 100644
--- a/src/main/java/org/apache/commons/math3/stat/inference/ChiSquareTest.java
+++ b/src/main/java/org/apache/commons/math3/stat/inference/ChiSquareTest.java
@@ -70,9 +70,8 @@ public class ChiSquareTest {
      * @param observed array of observed frequency counts
      * @param expected array of expected frequency counts
      * @return chiSquare test statistic
-     * @throws NotPositiveException if one element of <code>expected</code> is not
-     * positive
-     * @throws NotStrictlyPositiveException if one element of <code>observed</code> is
+     * @throws NotPositiveException if <code>observed</code> has negative entries
+     * @throws NotStrictlyPositiveException if <code>expected</code> has entries that are
      * not strictly positive
      * @throws DimensionMismatchException if the arrays length is less than 2
      */
@@ -144,9 +143,8 @@ public class ChiSquareTest {
      * @param observed array of observed frequency counts
      * @param expected array of expected frequency counts
      * @return p-value
-     * @throws NotPositiveException if one element of <code>expected</code> is not
-     * positive
-     * @throws NotStrictlyPositiveException if one element of <code>observed</code> is
+     * @throws NotPositiveException if <code>observed</code> has negative entries
+     * @throws NotStrictlyPositiveException if <code>expected</code> has entries that are
      * not strictly positive
      * @throws DimensionMismatchException if the arrays length is less than 2
      * @throws MaxCountExceededException if an error occurs computing the p-value
@@ -192,9 +190,8 @@ public class ChiSquareTest {
      * @param alpha significance level of the test
      * @return true iff null hypothesis can be rejected with confidence
      * 1 - alpha
-     * @throws NotPositiveException if one element of <code>expected</code> is not
-     * positive
-     * @throws NotStrictlyPositiveException if one element of <code>observed</code> is
+     * @throws NotPositiveException if <code>observed</code> has negative entries
+     * @throws NotStrictlyPositiveException if <code>expected</code> has entries that are
      * not strictly positive
      * @throws DimensionMismatchException if the arrays length is less than 2
      * @throws OutOfRangeException if <code>alpha</code> is not in the range (0, 0.5]
@@ -239,7 +236,7 @@ public class ChiSquareTest {
      * @return chiSquare test statistic
      * @throws NullArgumentException if the array is null
      * @throws DimensionMismatchException if the array is not rectangular
-     * @throws NotPositiveException if one entry is not positive
+     * @throws NotPositiveException if {@code counts} has negative entries
      */
     public double chiSquare(final long[][] counts)
         throws NullArgumentException, NotPositiveException,
@@ -303,7 +300,7 @@ public class ChiSquareTest {
      * @return p-value
      * @throws NullArgumentException if the array is null
      * @throws DimensionMismatchException if the array is not rectangular
-     * @throws NotPositiveException if one entry is not positive
+     * @throws NotPositiveException if {@code counts} has negative entries
      * @throws MaxCountExceededException if an error occurs computing the p-value
      */
     public double chiSquareTest(final long[][] counts)
@@ -352,7 +349,7 @@ public class ChiSquareTest {
      * 1 - alpha
      * @throws NullArgumentException if the array is null
      * @throws DimensionMismatchException if the array is not rectangular
-     * @throws NotPositiveException if one entry is not positive
+     * @throws NotPositiveException if {@code counts} has any negative entries
      * @throws OutOfRangeException if <code>alpha</code> is not in the range (0, 0.5]
      * @throws MaxCountExceededException if an error occurs computing the p-value
      */
@@ -400,10 +397,10 @@ public class ChiSquareTest {
      * @param observed2 array of observed frequency counts of the second data set
      * @return chiSquare test statistic
      * @throws DimensionMismatchException the the length of the arrays does not match
-     * @throws NotPositiveException if one entry in <code>observed1</code> or
-     * <code>observed2</code> is not positive
+     * @throws NotPositiveException if any entries in <code>observed1</code> or
+     * <code>observed2</code> are negative
      * @throws ZeroException if either all counts of <code>observed1</code> or
-     * <code>observed2</code> are zero, or if the count at the same index is zero
+     * <code>observed2</code> are zero, or if the count at some index is zero
      * for both arrays
      * @since 1.2
      */
@@ -496,8 +493,8 @@ public class ChiSquareTest {
      * @param observed2 array of observed frequency counts of the second data set
      * @return p-value
      * @throws DimensionMismatchException the the length of the arrays does not match
-     * @throws NotPositiveException if one entry in <code>observed1</code> or
-     * <code>observed2</code> is not positive
+     * @throws NotPositiveException if any entries in <code>observed1</code> or
+     * <code>observed2</code> are negative
      * @throws ZeroException if either all counts of <code>observed1</code> or
      * <code>observed2</code> are zero, or if the count at the same index is zero
      * for both arrays
@@ -548,8 +545,8 @@ public class ChiSquareTest {
      * @return true iff null hypothesis can be rejected with confidence
      * 1 - alpha
      * @throws DimensionMismatchException the the length of the arrays does not match
-     * @throws NotPositiveException if one entry in <code>observed1</code> or
-     * <code>observed2</code> is not positive
+     * @throws NotPositiveException if any entries in <code>observed1</code> or
+     * <code>observed2</code> are negative
      * @throws ZeroException if either all counts of <code>observed1</code> or
      * <code>observed2</code> are zero, or if the count at the same index is zero
      * for both arrays
@@ -579,7 +576,7 @@ public class ChiSquareTest {
      * @param in input 2-way table to check
      * @throws NullArgumentException if the array is null
      * @throws DimensionMismatchException if the array is not valid
-     * @throws NotPositiveException if one entry is not positive
+     * @throws NotPositiveException if the array contains any negative entries
      */
     private void checkArray(final long[][] in)
         throws NullArgumentException, DimensionMismatchException,