diff --git a/src/eva2/tools/math/Mathematics.java b/src/eva2/tools/math/Mathematics.java
index 1c4b39d5..c0146d4f 100644
--- a/src/eva2/tools/math/Mathematics.java
+++ b/src/eva2/tools/math/Mathematics.java
@@ -646,6 +646,15 @@ public final class Mathematics {
         return result;
     }
 
+    /**
+     * Performs two-sample unpaired t test and returns t critical value.
+     *
+     * Both samples have to have the same size and equal variance.
+     *
+     * @param vector1
+     * @param vector2
+     * @return
+     */
     public static double tTestEqSizeEqVar(double[] vector1, double[] vector2) {
         double n = (double) vector1.length;
         double mean1 = mean(vector1);
diff --git a/test/eva2/tools/math/MathematicsTest.java b/test/eva2/tools/math/MathematicsTest.java
index 2fd015e6..5d7a21a8 100644
--- a/test/eva2/tools/math/MathematicsTest.java
+++ b/test/eva2/tools/math/MathematicsTest.java
@@ -108,4 +108,12 @@ public class MathematicsTest {
     public void testScale() throws Exception {
 
     }
+
+    @Test
+    public void testTTestEqSizeEqVar() {
+        double[] values1 = {6,6,2,7,8,8,2,3,5,7,10,5,4,7,5,7,4,5,2,5,3,4,4,4,4};
+        double[] values2 = {6,11,8,5,11,8,10,7,4,3,7,6,10,10,6,5,10,11,13,8,5,11,7,8,5};
+
+        assertEquals(-4.05593, Mathematics.tTestEqSizeEqVar(values1, values2), 0.00001);
+    }
 }
\ No newline at end of file