org.moeaframework.util.statistics
Class SingleSampleTTest

java.lang.Object
  org.moeaframework.util.statistics.IntervalRatioStatisticalTest
      org.moeaframework.util.statistics.SingleSampleTTest

All Implemented Interfaces:

StatisticalTest

public class SingleSampleTTest
extends IntervalRatioStatisticalTest

The Single-Sample t test determines if the population's mean equals some specified value.

• Null Hypothesis: The population's mean equals X.
• Alternative Hypothesis: The population's mean does not equal X.

Assumptions:

1. Samples are randomly selected from the population
2. The distribution of the underlying population is normal

References:

1. Sheskin, D.J. "Handbook of Parametric and Nonparametric Statistical Procedures, Third Edition." Chapman & Hall/CRC. 2004.

Field Summary

Fields inherited from class org.moeaframework.util.statistics.IntervalRatioStatisticalTest

data, numberOfGroups

Constructor Summary

SingleSampleTTest(double mean)
Constructs a single-sample T test with the specified mean.

Method Summary

void	add(double value) Adds a new observation with the specified value.
void	addAll(double[] values) Adds several new observations with the specified values.
double	getMean() Returns the value being tested against the population mean.
boolean	test(double alpha) Returns true if the null hypothesis is rejected; false otherwise.

Methods inherited from class org.moeaframework.util.statistics.IntervalRatioStatisticalTest

add, addAll, categorize, getNumberOfGroups

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SingleSampleTTest

public SingleSampleTTest(double mean)

Constructs a single-sample T test with the specified mean.

Parameters:

mean - the value being tested against the population mean

Method Detail

getMean

public double getMean()

Returns the value being tested against the population mean.

Returns:

the value being tested against the population mean

add

public void add(double value)

Adds a new observation with the specified value.

Parameters:

value - the value of the new observation

addAll

public void addAll(double[] values)

Adds several new observations with the specified values.

Parameters:

values - the values of the new observations

test

public boolean test(double alpha)

Returns true if the null hypothesis is rejected; false otherwise. The meaning of the null hypothesis and alternative hypothesis depends on the specific test.

The prespecified level of confidence, alpha, can be used for either one-tailed or two-tailed (directional or nondirectional) distributions, depending on the specific test. Some tests may only support specific values for alpha.

Parameters:

alpha - the prespecified level of confidence

Returns:

true if the null hypothesis is rejected; false otherwise

See Also:

TestUtils.tTest(double, double[], double)