improved test coverage

Author: cicirello

tests/org/cicirello/math/stats/StatisticsTests.java

@@ -315,4 +315,32 @@ public void testCorrelationMatrixOfDoubles() {
 			}
 		}
 	}
+	
+	@Test
+	public void testWelchsTTestDoubles() {
+		double[] a1 = {27.5, 21.0, 19.0, 23.6, 17.0, 17.9, 
+			16.9, 20.1, 21.9, 22.6, 23.1, 19.6, 19.0, 21.7, 21.4};
+		double[] a2 = {27.1, 22.0, 20.8, 23.4, 23.4, 23.5, 
+			25.8, 22.0, 24.8, 20.2, 21.9, 22.1, 22.9, 20.5, 24.4};
+		assertEquals(-2.46, Statistics.tTestUnequalVariances(a1, a2), 0.01);
+		assertEquals(2.46, Statistics.tTestUnequalVariances(a2, a1), 0.01);
+		double[] b1 = {17.2, 20.9, 22.6, 18.1, 21.7, 21.4, 23.5, 24.2, 14.7, 21.8};
+		double[] b2 = {21.5, 22.8, 21.0, 23.0, 21.6, 23.6, 22.5, 20.7, 23.4, 21.8, 
+			20.7, 21.7, 21.5, 22.5, 23.6, 21.5, 22.5, 23.5, 21.5, 21.8};
+		assertEquals(-1.57, Statistics.tTestUnequalVariances(b1, b2), 0.01);
+		assertEquals(1.57, Statistics.tTestUnequalVariances(b2, b1), 0.01);
+		
+		Number[] result = Statistics.tTestWelch(a1, a2);
+		assertEquals(-2.46, (Double)result[0], 0.01);
+		assertEquals(24, ((Integer)result[1]).intValue());
+		result = Statistics.tTestWelch(a2, a1);
+		assertEquals(2.46, (Double)result[0], 0.01);
+		assertEquals(24, ((Integer)result[1]).intValue());
+		result = Statistics.tTestWelch(b1, b2);
+		assertEquals(-1.57, (Double)result[0], 0.01);
+		assertEquals(9, ((Integer)result[1]).intValue());
+		result = Statistics.tTestWelch(b2, b1);
+		assertEquals(1.57, (Double)result[0], 0.01);
+		assertEquals(9, ((Integer)result[1]).intValue());
+	}
 }