Class SampleStatistic

  • public class SampleStatistic
    extends java.lang.Object

    Statistics on a sampled value.

    Provides max, total, mean, count, variance, and standard deviation of continuous sequence of samples.

    Calculates estimates of mean, variance, and standard deviation characteristics of a sample using a non synchronized approximation of the on-line algorithm presented in Donald Knuth's Art of Computer Programming, Volume 2, Semi numerical Algorithms, 3rd edition, page 232, Boston: Addison-Wesley. That cites a 1962 paper by B.P. Welford: Note on a Method for Calculating Corrected Sums of Squares and Products

    This algorithm is also described in Wikipedia in the section "Online algorithm": Algorithms for calculating variance.

    • Constructor Detail

      • SampleStatistic

        public SampleStatistic()
    • Method Detail

      • reset

        public void reset()
        Resets the statistics.
      • record

        public void record​(long sample)
        Records a sample value.
        sample - the value to record.
      • set

        public void set​(long sample)
        use record(long) instead
        sample - the value to record.
      • getMax

        public long getMax()
        the max value of the recorded samples
      • getTotal

        public long getTotal()
        the sum of all the recorded samples
      • getCount

        public long getCount()
        the number of samples recorded
      • getMean

        public double getMean()
        the average value of the samples recorded, or zero if there are no samples
      • getVariance

        public double getVariance()
        the variance of the samples recorded, or zero if there are less than 2 samples
      • getStdDev

        public double getStdDev()
        the standard deviation of the samples recorded
      • toString

        public java.lang.String toString()
        toString in class java.lang.Object