Example usage for org.apache.commons.math3.stat StatUtils populationVariance

Introduction

In this page you can find the example usage for org.apache.commons.math3.stat StatUtils populationVariance.

Prototype

public static double populationVariance(final double[] values) throws MathIllegalArgumentException 

Source Link

Document

Returns the <a href="http://en.wikibooks.org/wiki/Statistics/Summary/Variance"> population variance</a> of the entries in the input array, or <code>Double.NaN</code> if the array is empty.

Usage

From source file:tech.tablesaw.api.NumberColumnTest.java

@Test
public void testSummarize() {
    IntColumn c = IntColumn.indexColumn("t", 99, 1);
    IntColumn c2 = c.copy();/*from  www  . ja  v a2  s .  c o  m*/
    c2.appendCell("");
    double c2Variance = c2.variance();
    double cVariance = StatUtils.variance(c.asDoubleArray());
    assertEquals(cVariance, c2Variance, 0.00001);
    assertEquals(StatUtils.sumLog(c.asDoubleArray()), c2.sumOfLogs(), 0.00001);
    assertEquals(StatUtils.sumSq(c.asDoubleArray()), c2.sumOfSquares(), 0.00001);
    assertEquals(StatUtils.geometricMean(c.asDoubleArray()), c2.geometricMean(), 0.00001);
    assertEquals(StatUtils.product(c.asDoubleArray()), c2.product(), 0.00001);
    assertEquals(StatUtils.populationVariance(c.asDoubleArray()), c2.populationVariance(), 0.00001);
    assertEquals(new DescriptiveStatistics(c.asDoubleArray()).getQuadraticMean(), c2.quadraticMean(), 0.00001);
    assertEquals(new DescriptiveStatistics(c.asDoubleArray()).getStandardDeviation(), c2.standardDeviation(),
            0.00001);
    assertEquals(new DescriptiveStatistics(c.asDoubleArray()).getKurtosis(), c2.kurtosis(), 0.00001);
    assertEquals(new DescriptiveStatistics(c.asDoubleArray()).getSkewness(), c2.skewness(), 0.00001);

    assertEquals(StatUtils.variance(c.asDoubleArray()), c.variance(), 0.00001);
    assertEquals(StatUtils.sumLog(c.asDoubleArray()), c.sumOfLogs(), 0.00001);
    assertEquals(StatUtils.sumSq(c.asDoubleArray()), c.sumOfSquares(), 0.00001);
    assertEquals(StatUtils.geometricMean(c.asDoubleArray()), c.geometricMean(), 0.00001);
    assertEquals(StatUtils.product(c.asDoubleArray()), c.product(), 0.00001);
    assertEquals(StatUtils.populationVariance(c.asDoubleArray()), c.populationVariance(), 0.00001);
    assertEquals(new DescriptiveStatistics(c.asDoubleArray()).getQuadraticMean(), c.quadraticMean(), 0.00001);
    assertEquals(new DescriptiveStatistics(c.asDoubleArray()).getStandardDeviation(), c.standardDeviation(),
            0.00001);
    assertEquals(new DescriptiveStatistics(c.asDoubleArray()).getKurtosis(), c.kurtosis(), 0.00001);
    assertEquals(new DescriptiveStatistics(c.asDoubleArray()).getSkewness(), c.skewness(), 0.00001);
}

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