public void TTestConstructorTest()
{
// mean = 0.5, var = 1
double[] sample =
{
-0.849886940156521, 3.53492346633185, 1.22540422494611, 0.436945126810344, 1.21474290382610,
0.295033941700225, 0.375855651783688, 1.98969760778547, 1.90903448980048, 1.91719241342961
};
// Null Hypothesis: Values are equal
// Alternative : Values are different
double hypothesizedMean = 0;
OneSampleHypothesis hypothesis = OneSampleHypothesis.ValueIsDifferentFromHypothesis;
TTest target = new TTest(sample, hypothesizedMean, hypothesis);
Assert.AreEqual(3.1254485381338246, target.Statistic);
Assert.AreEqual(OneSampleHypothesis.ValueIsDifferentFromHypothesis, target.Hypothesis);
Assert.AreEqual(DistributionTail.TwoTail, target.Tail);
Assert.AreEqual(0.012210924322697769, target.PValue);
Assert.IsTrue(target.Significant);
// Null hypothesis: value is smaller than hypothesis
// Alternative : value is greater than hypothesis
// If the null hypothesis states that the population parameter is less
// than zero (or a constant), the z-score that rejects the null is always
// positive and greater than the score set for the rejection condition.
hypothesis = OneSampleHypothesis.ValueIsGreaterThanHypothesis;
target = new TTest(sample, hypothesizedMean, hypothesis);
// z-score is positive:
Assert.AreEqual(3.1254485381338246, target.Statistic);
Assert.AreEqual(OneSampleHypothesis.ValueIsGreaterThanHypothesis, target.Hypothesis); // right tail
Assert.AreEqual(DistributionTail.OneUpper, target.Tail); // right tail
Assert.AreEqual(0.0061054621613488846, target.PValue);
Assert.IsTrue(target.Significant); // null should be rejected
// Null hypothesis: value is greater than hypothesis
// Alternative: value is smaller than hypothesis
// If the null hypothesis states that the population parameter is
// greater than zero (or a constant), the z-score that rejects the
// null is always negative and less than the score set for the
// rejection condition.
hypothesis = OneSampleHypothesis.ValueIsSmallerThanHypothesis;
target = new TTest(sample, hypothesizedMean, hypothesis);
// z-score is positive:
Assert.AreEqual(3.1254485381338246, target.Statistic);
Assert.AreEqual(OneSampleHypothesis.ValueIsSmallerThanHypothesis, target.Hypothesis); // left tail
Assert.AreEqual(DistributionTail.OneLower, target.Tail); // left tail
Assert.AreEqual(0.99389453783865112, target.PValue);
Assert.IsFalse(target.Significant); // null cannot be rejected
}
