OneSampleTTest Class

Represents a test that the population mean of a Vector<T> is equal to a specific value.

Definition

Namespace: Numerics.NET.Statistics.Tests
Assembly: Numerics.NET (in Numerics.NET.dll) Version: 9.1.2
C#
public sealed class OneSampleTTest : OneSampleTest
Inheritance
Object  →  HypothesisTest  →  OneSampleTest<Double>  →  OneSampleTest  →  OneSampleTTest

Remarks

Use the OneSampleTTest to test the hypothesis that the mean of a variable is equal to a specified value. The variable is a sample from a population with a normal distribution.

The null hypothesis for the one-sample t-test is that the population mean is equal to the specified value. The test statistic follows a Student's t distribution with degrees of freedom equal to the sample size minus one.

This test is commonly used in situations where the population variance is unknown and the sample size is small. It is applicable in various fields such as psychology, medicine, and social sciences to determine if a sample mean significantly differs from a known or hypothesized population mean.

The sample data can be supplied either as a Vector<T>, or by specifying the SampleMean, SampleStandardDeviation and the SampleSize.

A confidence interval for the variance of the sample can be obtained using the GetConfidenceInterval(Double) method.

When the population variance is known, use a OneSampleZTest. To compare two sample means, use a TwoSampleTTest.

Example

The following example demonstrates how to perform a one-sample t-test using the OneSampleTTest class. It creates a sample vector, performs the test, and then displays the test statistic, p-value, and confidence interval.

C#
using System;
using Numerics.NET;
using Numerics.NET.Statistics;
using Numerics.NET.Statistics.Tests;

Vector<double> sampleData = [ 2.3, 2.5, 2.8, 3.0, 3.2 ];
double hypothesizedMean = 2.5;

var tTest = new OneSampleTTest(sampleData, hypothesizedMean);
double testStatistic = tTest.CalculateStatistic();
double pValue = tTest.GetPValue(HypothesisType.TwoTailed);
var confidenceInterval = tTest.GetConfidenceInterval(0.95);

Console.WriteLine($"Test Statistic: {testStatistic}");
Console.WriteLine($"P-Value: {pValue}");
Console.WriteLine($"95% Confidence Interval: [{confidenceInterval.LowerBound}, {confidenceInterval.UpperBound}]");

Constructors

OneSampleTTest() Constructs a new OneSampleTTest.
OneSampleTTest(Vector<Double>, Double) Constructs a new OneSampleTTest for the specified Vector<T>.
OneSampleTTest(Vector<Double>, Double, HypothesisType) Constructs a new OneSampleTTest for the specified Vector<T> with known standard deviation.
OneSampleTTest(Double, Double, Int32, Double) Constructs a new OneSampleTTest for the specified Vector<T>.
OneSampleTTest(Double, Double, Int32, Double, HypothesisType) Constructs a new OneSampleTTest for the specified Vector<T> with known standard deviation.

Properties

CohenD Gets the effect size measured as Cohen's d.
Distribution Gets the probability distribution used in the hypothesis test.
(Inherited from HypothesisTest)
HedgesG Gets the effect size measured as Hedges' g.
HypothesisType Gets or sets whether the test is one or two-tailed.
(Inherited from HypothesisTest)
Mean Gets or sets the mean value to compare to.
Name Gets the name of the hypothesis test.
(Overrides HypothesisTest.Name)
PValue Gets the probability that the test statistic would take on the calculated value under the alternate hypothesis.
(Inherited from HypothesisTest)
Sample Gets or sets the variable the test is to be applied to.
(Inherited from OneSampleTest<T>)
SampleMean Gets or sets the mean of the sample.
SampleSize Gets or sets the size of the sample.
SampleStandardDeviation Gets or sets the standard deviation of the sample.
SignificanceLevel Gets the significance level used to test the null hypothesis.
(Inherited from HypothesisTest)
Statistic Gets the value of the test statistic.
(Inherited from HypothesisTest)

Methods

EqualsDetermines whether the specified object is equal to the current object.
(Inherited from Object)
GetConfidenceInterval() Returns the confidence interval for the test parameter for the default confidence level.
(Inherited from HypothesisTest)
GetConfidenceInterval(Double) Returns the confidence interval for the mean of the population for the specified confidence level.
(Overrides HypothesisTest.GetConfidenceInterval(Double))
GetHashCodeServes as the default hash function.
(Inherited from Object)
GetLowerCriticalValue() Gets the lower critical value for the hypothesis test's current significance level.
(Inherited from HypothesisTest)
GetLowerCriticalValue(Double) Gets the lower critical value for the hypothesis test at the specified significance level.
(Inherited from HypothesisTest)
GetPValue Gets the probability that the test statistic would take on the calculated value under the specified alternate hypothesis.
(Inherited from HypothesisTest)
GetTypeGets the Type of the current instance.
(Inherited from Object)
GetUpperCriticalValue() Gets the upper critical value for the test statistic at the hypothesis test's current significance level.
(Inherited from HypothesisTest)
GetUpperCriticalValue(Double) Gets the upper critical value for the test statistic at the specified significance level.
(Inherited from HypothesisTest)
Reject() Returns whether the null hypothesis is rejected using the default significance level.
(Inherited from HypothesisTest)
Reject(Double) Returns whether the null hypothesis is rejected using the specified significance level.
(Inherited from HypothesisTest)
Summarize() Returns a string containing a human-readable summary of the object.
(Inherited from HypothesisTest)
Summarize(SummaryOptions) Returns a string containing a human-readable summary of the object using the specified options.
(Inherited from OneSampleTest<T>)
ToStringReturns a string that represents the current object.
(Inherited from HypothesisTest)

See Also