BasicStats { public static double stdDevForGivenMean(Path input, Path output, double mean, Configuration baseConf) throws IOException, InterruptedException, ClassNotFoundException { return Math.sqrt(varianceForGivenMean(input, output, mean, baseConf)); } private  BasicStats(); static double variance(Path input, Path output,
                                Configuration baseConf); static double varianceForGivenMean(Path input, Path output, double mean,
                                Configuration baseConf); static double stdDev(Path input, Path output,
                              Configuration baseConf); static double stdDevForGivenMean(Path input, Path output, double mean,
                              Configuration baseConf);  }
@Test public void testStdDevForGivenMean() throws Exception { Path input = getTestTempFilePath("stdDev/counts.file"); Path output = getTestTempFilePath("stdDev/output.file"); produceTestData(input); double v = BasicStats.stdDevForGivenMean(input, output, 0.0D, conf); assertEquals(10.65, v, 0.01); }