public void WilcoxonSignedRankTestConstructorTest()
{
double[] sample = { 17, 50, 45, 59.8, 21.74, 16, 9, 15.43, 5.12, 40, 35, 13.35, 13.4 };
double hypothesizedMedian = 7.38;
var target = new WilcoxonSignedRankTest(sample, hypothesizedMedian);
Assert.AreEqual(OneSampleHypothesis.ValueIsDifferentFromHypothesis, target.Hypothesis);
double[] delta = { 9.62, 42.62, 37.62, 52.42, 14.36, 8.62, 1.62, 8.05, 2.26, 32.62, 27.62, 5.97, 6.02 };
double[] ranks = { 7, 12, 11, 13, 8, 6, 1, 5, 2, 10, 9, 3, 4 };
Assert.IsTrue(delta.IsEqual(target.Delta, 1e-6));
Assert.IsTrue(ranks.IsEqual(target.Ranks, 1e-6));
Assert.AreEqual(89, target.Statistic);
Assert.AreEqual(0.003, target.PValue, 1e-3);
Assert.IsTrue(target.Significant);
}
public void WilcoxonSignedRankTestConstructorTest2()
{
// Example from https://onlinecourses.science.psu.edu/stat414/node/319
double[] sample = { 5.0, 3.9, 5.2, 5.5, 2.8, 6.1, 6.4, 2.6, 1.7, 4.3 };
double hypothesizedMedian = 3.7;
var target = new WilcoxonSignedRankTest(sample, hypothesizedMedian);
Assert.AreEqual(OneSampleHypothesis.ValueIsDifferentFromHypothesis, target.Hypothesis);
// Absolute differences and original signs
double[] delta = { +1.3, +0.2, +1.5, +1.8, +0.9, +2.4, +2.7, +1.1, +2.0, +0.6 };
double[] signs = { +1.0, +1.0, +1.0, +1.0, -1.0, -1.0, +1.0, -1.0, -1.0, +1.0 };
double[] ranks = { +5.0, +1.0, +6.0, +7.0, +3.0, +9.0, +10, +4.0, +8.0, +2.0 };
Assert.AreEqual(40, target.Statistic);
Assert.AreEqual(0.232, target.PValue, 1e-3);
Assert.IsFalse(target.Significant);
}
public void WilcoxonSignedRankTestConstructorTest3()
{
// Example from https://onlinecourses.science.psu.edu/stat414/node/319
double[] sample =
{
35.5, 44.5, 39.8, 33.3, 51.4, 51.3, 30.5, 48.9, 42.1, 40.3,
46.8, 38.0, 40.1, 36.8, 39.3, 65.4, 42.6, 42.8, 59.8, 52.4,
26.2, 60.9, 45.6, 27.1, 47.3, 36.6, 55.6, 45.1, 52.2, 43.5,
};
double hypothesizedMedian = 45;
var target = new WilcoxonSignedRankTest(sample, hypothesizedMedian);
Assert.AreEqual(OneSampleHypothesis.ValueIsDifferentFromHypothesis, target.Hypothesis);
Assert.AreEqual(200, target.Statistic);
Assert.AreEqual(0.510, target.PValue, 1e-3);
Assert.IsFalse(target.Significant);
}
public void ConstructorTest2()
{
// This example has been adapted from the Wikipedia's page about
// the Z-Test, available from: http://en.wikipedia.org/wiki/Z-test
// We would like to check whether a sample of 20
// students with a median score of 96 points ...
double[] sample =
{
106, 115, 96, 88, 91, 88, 81, 104, 99, 68,
104, 100, 77, 98, 96, 104, 82, 94, 72, 96
};
// ... could have happened just by chance inside a
// population with an hypothesized median of 100 points.
double hypothesizedMedian = 100;
// So we start by creating the test:
WilcoxonSignedRankTest test = new WilcoxonSignedRankTest(sample,
hypothesizedMedian, OneSampleHypothesis.ValueIsSmallerThanHypothesis);
// Now, we can check whether this result would be
// unlikely under a standard significance level:
bool significant = test.Significant; // false (so the event was likely)
// We can also check the test statistic and its P-Value
double statistic = test.Statistic; // 40.0
double pvalue = test.PValue; // 0.98585347446367344
Assert.AreEqual(96, sample.Median());
Assert.AreEqual(statistic, 40.0);
Assert.AreEqual(pvalue, 0.98585347446367344);
}
