diff --git a/src/test/org/apache/commons/math/distribution/ChiSquareDistributionTest.java b/src/test/org/apache/commons/math/distribution/ChiSquareDistributionTest.java
new file mode 100644
index 000000000..40b553b88
--- /dev/null
+++ b/src/test/org/apache/commons/math/distribution/ChiSquareDistributionTest.java
@@ -0,0 +1,129 @@
+/* ====================================================================
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2003 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Commons", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+package org.apache.commons.math.stat.distribution;
+
+import junit.framework.TestCase;
+
+/**
+ * @author Brent Worden
+ */
+public class ChiSquareDistributionTest extends TestCase {
+    private ChiSquaredDistribution chiSquare;
+    
+	/**
+	 * Constructor for ChiSquareDistributionTest.
+	 * @param name
+	 */
+	public ChiSquareDistributionTest(String name) {
+		super(name);
+	}
+
+	/*
+	 * @see TestCase#setUp()
+	 */
+	protected void setUp() throws Exception {
+		super.setUp();
+        chiSquare = DistributionFactory.newInstance().createChiSquareDistribution(5.0);
+	}
+
+	/*
+	 * @see TestCase#tearDown()
+	 */
+	protected void tearDown() throws Exception {
+        chiSquare = null;
+		super.tearDown();
+	}
+
+    public void testLowerTailProbability(){
+        testProbability( .210, .001);
+        testProbability( .554, .010);
+        testProbability( .831, .025);
+        testProbability(1.145, .050);
+        testProbability(1.610, .100);
+    }
+
+    public void testUpperTailProbability(){
+        testProbability(20.515, .999);
+        testProbability(15.086, .990);
+        testProbability(12.833, .975);
+        testProbability(11.070, .950);
+        testProbability( 9.236, .900);
+    }
+    
+    public void testLowerTailValues(){
+        testValue(.001,  .210);
+        testValue(.010,  .554);
+        testValue(.025,  .831);
+        testValue(.050, 1.145);
+        testValue(.100, 1.610);
+    }
+    
+    public void testUpperTailValues(){
+        testValue(.999, 20.515);
+        testValue(.990, 15.086);
+        testValue(.975, 12.833);
+        testValue(.950, 11.070);
+        testValue(.900,  9.236);
+    }
+    
+    private void testProbability(double x, double expected){
+        double actual = chiSquare.cummulativeProbability(x);
+        assertEquals("probability for " + x, expected, actual, 10e-4);
+    }
+    
+    private void testValue(double p, double expected){
+        double actual = chiSquare.inverseCummulativeProbability(p);
+        assertEquals("value for " + p, expected, actual, 10e-4);
+    }
+}
diff --git a/src/test/org/apache/commons/math/distribution/DistributionFactoryImplTest.java b/src/test/org/apache/commons/math/distribution/DistributionFactoryImplTest.java
new file mode 100644
index 000000000..5b09492d7
--- /dev/null
+++ b/src/test/org/apache/commons/math/distribution/DistributionFactoryImplTest.java
@@ -0,0 +1,183 @@
+/* ====================================================================
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2003 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Commons", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+package org.apache.commons.math.stat.distribution;
+
+import junit.framework.TestCase;
+
+/**
+ * @author Brent Worden
+ */
+public class DistributionFactoryImplTest extends TestCase {
+    /** */
+    private DistributionFactory factory;
+    
+	/**
+	 * Constructor for DistributionFactoryImplTest.
+	 * @param name
+	 */
+	public DistributionFactoryImplTest(String name) {
+		super(name);
+	}
+	/**
+	 * @throws java.lang.Exception
+	 */
+	protected void setUp() throws Exception {
+		super.setUp();
+        factory = new DistributionFactoryImpl();
+	}
+
+	/**
+	 * @throws java.lang.Exception
+	 */
+	protected void tearDown() throws Exception {
+        factory = null;
+		super.tearDown();
+	}
+    
+    public void testCreateChiSquareDistributionNegative(){
+        try {
+            factory.createChiSquareDistribution(-1.0);
+            fail("negative degrees of freedom.  IllegalArgumentException expected");
+        } catch (IllegalArgumentException ex) {
+            ;
+        }
+    }
+    
+    public void testCreateChiSquareDistributionZero(){
+        try {
+            factory.createChiSquareDistribution(0.0);
+            fail("zero degrees of freedom.  IllegalArgumentException expected");
+        } catch (IllegalArgumentException ex) {
+            ;
+        }
+    }
+    
+    public void testCreateChiSquareDistributionPositive(){
+        try {
+            factory.createChiSquareDistribution(1.0);
+        } catch (IllegalArgumentException ex) {
+            fail("positive degrees of freedom.  IllegalArgumentException is not expected");
+        }
+    }
+    
+    public void testCreateGammaDistributionNegativePositive(){
+        try {
+            factory.createGammaDistribution(-1.0, 1.0);
+            fail("negative alpha.  IllegalArgumentException expected");
+        } catch (IllegalArgumentException ex) {
+            ;
+        }
+    }
+    
+    public void testCreateGammaDistributionZeroPositive(){
+        try {
+            factory.createGammaDistribution(0.0, 1.0);
+            fail("zero alpha.  IllegalArgumentException expected");
+        } catch (IllegalArgumentException ex) {
+            ;
+        }
+    }
+    
+    public void testCreateGammaDistributionPositiveNegative(){
+        try {
+            factory.createGammaDistribution(1.0, -1.0);
+            fail("negative beta.  IllegalArgumentException expected");
+        } catch (IllegalArgumentException ex) {
+            ;
+        }
+    }
+    
+    public void testCreateGammaDistributionPositiveZero(){
+        try {
+            factory.createGammaDistribution(1.0, 0.0);
+            fail("zero beta.  IllegalArgumentException expected");
+        } catch (IllegalArgumentException ex) {
+            ;
+        }
+    }
+    
+    public void testCreateGammaDistributionPositivePositive(){
+        try {
+            factory.createGammaDistribution(1.0, 1.0);
+        } catch (IllegalArgumentException ex) {
+            fail("positive alpah and beta.  IllegalArgumentException is not expected");
+        }
+    }
+//    
+//    public void testCreateTDistributionNegative(){
+//        try {
+//            factory.createTDistribution(-1.0);
+//            fail("negative degrees of freedom.  IllegalArgumentException expected");
+//        } catch (IllegalArgumentException ex) {
+//            ;
+//        }
+//    }
+//    
+//    public void testCreateTDistributionZero(){
+//        try {
+//            factory.createTDistribution(0.0);
+//            fail("zero degrees of freedom.  IllegalArgumentException expected");
+//        } catch (IllegalArgumentException ex) {
+//            ;
+//        }
+//    }
+//    
+//    public void testCreateTDistributionPositive(){
+//        try {
+//            factory.createTDistribution(1.0);
+//        } catch (IllegalArgumentException ex) {
+//            fail("positive degrees of freedom.  IllegalArgumentException is not expected");
+//        }
+//    }
+}
diff --git a/src/test/org/apache/commons/math/distribution/GammaDistributionTest.java b/src/test/org/apache/commons/math/distribution/GammaDistributionTest.java
new file mode 100644
index 000000000..860a5d307
--- /dev/null
+++ b/src/test/org/apache/commons/math/distribution/GammaDistributionTest.java
@@ -0,0 +1,81 @@
+/* ====================================================================
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2003 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Commons", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+package org.apache.commons.math.stat.distribution;
+
+import junit.framework.TestCase;
+
+/**
+ * @author Brent Worden
+ */
+public class GammaDistributionTest extends TestCase {
+	/**
+	 * Constructor for ChiSquareDistributionTest.
+	 * @param name
+	 */
+	public GammaDistributionTest(String name) {
+		super(name);
+	}
+
+    public void testProbabilities(){
+        testProbability(15.5, 4.0, 2.0, .9499);
+        testProbability( 0.5, 4.0, 1.0, .0018);
+        testProbability(10.0, 1.0, 2.0, .9933);
+        testProbability( 5.0, 2.0, 2.0, .7127);
+    }
+    
+    private void testProbability(double x, double a, double b, double expected){
+        double actual = DistributionFactory.newInstance().createGammaDistribution(a, b).cummulativeProbability(x);
+        assertEquals("probability for " + x, expected, actual, 10e-4);
+    }
+}