Class Statistics

public static double calculateMean(Collection values)

Returns the mean of a collection of Number objects.

Parameters:

values - the values (null permitted, returns Double.NaN).

Returns:

The mean.

public static double calculateMean(Number[] values)

Returns the mean of an array of numbers.

Parameters:

values - the values (null permitted, returns Double.NaN).

Returns:

The mean.

public static double calculateMedian(List values)

Calculates the median for a list of values (Number objects). The list of values will be sorted first.

Parameters:

values - the values.

Returns:

The median.

public static double calculateMedian(List values,
                                     boolean copyAndSort)

Calculates the median for a list of values (Number objects) that are assumed to be in ascending order.

Parameters:

values - the values.

copyAndSort - a flag that controls whether the list of values is copied and sorted.

Returns:

The median.

public static double calculateMedian(List values,
                                     int start,
                                     int end)

Calculates the median for a sublist within a list of values (Number objects).

Parameters:

values - the values (in any order).

start - the start index.

end - the end index.

Returns:

The median.

public static double calculateMedian(List values,
                                     int start,
                                     int end,
                                     boolean copyAndSort)

Calculates the median for a sublist within a list of values (Number objects). The entire list will be sorted if the ascendingfalse.

Parameters:

values - the values.

start - the start index.

end - the end index.

copyAndSort - a flag that that controls whether the list of values is copied and sorted.

Returns:

The median.

public static double getCorrelation(Number[] data1,
                                    Number[] data2)

Calculates the correlation between two datasets. Both arrays should contain the same number of items. Null values are treated as zero.

Information about the correlation calculation was obtained from: http://trochim.human.cornell.edu/kb/statcorr.htm

Parameters:

data1 - the first dataset.

data2 - the second dataset.

Returns:

The correlation.

public static double[] getLinearFit(Number[] xData,
                                    Number[] yData)

Fits a straight line to a set of (x, y) data, returning the slope and intercept.

Parameters:

xData - the x-data.

yData - the y-data.

Returns:

A double array with the intercept in [0] and the slope in [1].

public static double[][] getMovingAverage(Number[] xData,
                                          Number[] yData,
                                          int period)

Returns a data set for a moving average on the data set passed in.

Parameters:

xData - an array of the x data.

yData - an array of the y data.

period - the number of data points to average

Returns:

A double[][] the length of the data set in the first dimension, with two doubles for x and y in the second dimension

public static double getSlope(Number[] xData,
                              Number[] yData)

Finds the slope of a regression line using least squares.

Parameters:

xData - an array of Numbers (the x values).

yData - an array of Numbers (the y values).

Returns:

The slope.

public static double getStdDev(Number[] data)

Returns the standard deviation of a set of numbers.

Parameters:

data - the data.

Returns:

The standard deviation of a set of numbers.