## org.eclipse.jetty.util.statistic Class SampleStatistic

```java.lang.Object org.eclipse.jetty.util.statistic.SampleStatistic
```

`public class SampleStatisticextends Object`

SampledStatistics

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, Seminumerical Algorithms, 3rd edition, page 232, Boston: Addison-Wesley. that cites a 1962 paper by B.P. Welford that can be found by following the link http://www.jstor.org/pss/1266577

This algorithm is also described in Wikipedia at http://en.wikipedia.org/w/index.php?title=Algorithms_for_calculating_variance§ion=4#On-line_algorithm

Field Summary
`protected  AtomicLong` `_count`

`protected  AtomicLong` `_max`

`protected  AtomicLong` `_total`

`protected  AtomicLong` `_totalVariance100`

Constructor Summary
`SampleStatistic()`

Method Summary
` long` `getCount()`

` long` `getMax()`

` double` `getMean()`

` double` `getStdDev()`

` long` `getTotal()`

` double` `getVariance()`

` void` `reset()`

` void` `set(long sample)`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### _max

`protected final AtomicLong _max`

### _total

`protected final AtomicLong _total`

### _count

`protected final AtomicLong _count`

### _totalVariance100

`protected final AtomicLong _totalVariance100`
Constructor Detail

### SampleStatistic

`public SampleStatistic()`
Method Detail

### reset

`public void reset()`

### set

`public void set(long sample)`

### getMax

`public long getMax()`
Returns:
the max value

### getTotal

`public long getTotal()`

### getCount

`public long getCount()`

### getMean

`public double getMean()`

### getVariance

`public double getVariance()`

### getStdDev

`public double getStdDev()`