Java: Data Science Made Easy

Using Apache Commons to find the median

We can also calculate the median using the Apache Commons DescriptiveStatistics class demonstrated in the Calculating the mean section. We will continue using the testData array with the following values:

double[] testData = {12.5, 18.3, 11.2, 19.0, 22.1, 14.3, 16.2, 12.5,   17.8, 16.5, 12.5}; 

Our code is very similar to what we used to calculate the mean. We simply create our DescriptiveStatistics object and call the getPercentile method, which returns an estimate of the value stored at the percentile specified in its argument. To find the median, we use the value of 50:

DescriptiveStatistics statTest =      new SynchronizedDescriptiveStatistics(); for(double num : testData){  statTest.addValue(num); ...