Examples of org.apache.commons.math.stat.descriptive.moment.Mean.evaluate()

org.apache.commons.math.stat.descriptive.moment.Mean.evaluate()

Returns the arithmetic mean of the entries in the specified portion of the input array, or Double.NaN if the designated subarray is empty.

Throws IllegalArgumentException if the array is null.

See {@link Mean} for details on the computing algorithm.

@param values the input array @param begin index of the first array element to include @param length the number of elements to include @return the mean of the values or Double.NaN if length = 0 @throws IllegalArgumentException if the array is null or the array indexparameters are not valid

        throws IllegalArgumentException {
        Mean mean = new Mean();
        double result = 0d;
        int length = xArray.length;
        if(length == yArray.length && length > 1) {
            double xMean = mean.evaluate(xArray);
            double yMean = mean.evaluate(yArray);
            for (int i = 0; i < length; i++) {
                double xDev = xArray[i] - xMean;
                double yDev = yArray[i] - yMean;
                result += (xDev * yDev - result) / (i + 1);

        Mean mean = new Mean();
        double result = 0d;
        int length = xArray.length;
        if(length == yArray.length && length > 1) {
            double xMean = mean.evaluate(xArray);
            double yMean = mean.evaluate(yArray);
            for (int i = 0; i < length; i++) {
                double xDev = xArray[i] - xMean;
                double yDev = yArray[i] - yMean;
                result += (xDev * yDev - result) / (i + 1);
            }

        values[i++] = rc.doubleValue();
      }
      StandardDeviation stdDev = new StandardDeviation();
      Mean mean = new Mean();
      double std = stdDev.evaluate(values);
      double m = mean.evaluate(values);
      System.out.println("mean: " + m + " std dev: " + std);
      //Assert.assertTrue(std < 0.1 * m);
      assertEquals(31000, count);
    }
  }

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