public void ConstructorTest()
{
var t = new TDistribution(degreesOfFreedom: 4.2);
double mean = t.Mean; // 0.0
double median = t.Median; // 0.0
double var = t.Variance; // 1.9090909090909089
double mode = t.Mode;
double cdf = t.DistributionFunction(x: 1.4); // 0.88456136730659074
double pdf = t.ProbabilityDensityFunction(x: 1.4); // 0.13894002185341031
double lpdf = t.LogProbabilityDensityFunction(x: 1.4); // -1.9737129364307417
double ccdf = t.ComplementaryDistributionFunction(x: 1.4); // 0.11543863269340926
double icdf = t.InverseDistributionFunction(p: cdf); // 1.4000000000000012
double hf = t.HazardFunction(x: 1.4); // 1.2035833984833988
double chf = t.CumulativeHazardFunction(x: 1.4); // 2.1590162088918525
string str = t.ToString(CultureInfo.InvariantCulture); // T(x; df = 4.2)
Assert.AreEqual(double.NegativeInfinity, t.Support.Min);
Assert.AreEqual(double.PositiveInfinity, t.Support.Max);
double icdf0 = t.InverseDistributionFunction(0);
double icdf1 = t.InverseDistributionFunction(1);
Assert.AreEqual(icdf0, t.Support.Min);
Assert.AreEqual(icdf1, t.Support.Max);
Assert.AreEqual(0.0, mean);
Assert.AreEqual(0.0, median);
Assert.AreEqual(0.0, mode);
Assert.AreEqual(1.9090909090909089, var);
Assert.AreEqual(2.1590162088918525, chf);
Assert.AreEqual(0.88456136730659074, cdf);
Assert.AreEqual(0.13894002185341031, pdf);
Assert.AreEqual(-1.9737129364307417, lpdf);
Assert.AreEqual(1.2035833984833988, hf);
Assert.AreEqual(0.11543863269340926, ccdf);
Assert.AreEqual(1.4000000000000012, icdf);
Assert.AreEqual("T(x; df = 4.2)", str);
var range1 = t.GetRange(0.95);
var range2 = t.GetRange(0.99);
var range3 = t.GetRange(0.01);
Assert.AreEqual(-2.1030107450099362, range1.Min);
Assert.AreEqual(2.1030107450099362, range1.Max);
Assert.AreEqual(-3.6502571302187774, range2.Min);
Assert.AreEqual(3.6502571302187774, range2.Max);
Assert.AreEqual(-3.6502571302187792, range3.Min);
Assert.AreEqual(3.6502571302187774, range3.Max);
}
private void CalculateAndWriteContrastValues()
{
// Calculations
List <double> meanValues = new List <double>();
List <double> effects = new List <double>();
double[][] measurements = GetMeasurements();
double SSE = 0.0, Se2, t = 0.0;
// Get alternative's measurements and calculate their mean value
for (int i = 0; i < measurements.Length; ++i)
{
meanValues.Add(measurements[i].Average());
}
// Calculate total mean value
double totalMeanValue = measurements.Select(x => x.Sum()).Sum() / (MeasurementsCount * AlternativesCount);
// Calculate effects
foreach (double meanValue in meanValues)
{
effects.Add(meanValue - totalMeanValue);
}
if (!effects.Any(x => x != 0.0))
{
WriteMessage("Enter measurements.");
return;
}
for (int i = 0; i < AlternativesCount; ++i)
{
for (int j = 0; j < MeasurementsCount; ++j)
{
SSE += Math.Pow(measurements[i][j] - meanValues[i], 2);
}
}
Se2 = SSE / (AlternativesCount * (MeasurementsCount - 1));
double Sc = Math.Sqrt(Se2 * 2 / (MeasurementsCount * AlternativesCount));
if (string.IsNullOrEmpty(PercentageTextBox.Text))
{
WriteMessage("Percentage must be specified.");
return;
}
double percentage = double.Parse(PercentageTextBox.Text);
if (percentage >= 1.0 || percentage < 0.0 || percentage == 0.5)
{
WriteMessage("Percentage must be in correct format (decimal form). Must not be 100%(1.0) or 50%(0.5).");
return;
}
// Find interval around Sc
int degOfFreedom = AlternativesCount * (MeasurementsCount - 1);
double percentageNumber = 1 - (1 - percentage) / 2;
if (MeasurementsCount <= 30)
{
TDistribution distribution = new TDistribution(degOfFreedom);
t = distribution.GetRange(percentageNumber).Max;
}
else
{
NormalDistribution distribution = new NormalDistribution();
t = distribution.GetRange(percentageNumber).Max;
}
double constantFactor = t * Sc;
int index = 1;
for (int i = 0; i < AlternativesCount; ++i)
{
for (int j = i + 1; j < AlternativesCount; ++j)
{
double c = effects[i] - effects[j];
((TextBlock)ContrastsGrid.Children.Cast <UIElement>().First(e => Grid.GetRow(e) == 1 && Grid.GetColumn(e) == index)).Text =
(c - constantFactor) < 0 && (c + constantFactor) >= 0 ? "Statistically the same." : "Statistically different.";
index++;
}
}
}