# Package org.apache.commons.math3.stat.descriptive

Generic univariate summary statistic objects.

See: Description

Interface Summary
Interface | Description
--- | ---
StatisticalMultivariateSummary | Reporting interface for basic multivariate statistics.
StatisticalSummary | Reporting interface for basic univariate statistics.
StorelessUnivariateStatistic | Extends the definition of `UnivariateStatistic` with `StorelessUnivariateStatistic.increment(double)` and `StorelessUnivariateStatistic.incrementAll(double[])` methods for adding values and updating internal state.
UnivariateStatistic | Base interface implemented by all statistics.
WeightedEvaluation | Weighted evaluation for statistics.

Class Summary
Class | Description
--- | ---
AbstractStorelessUnivariateStatistic | Abstract implementation of the `StorelessUnivariateStatistic` interface.
AbstractUnivariateStatistic | Abstract base class for all implementations of the `UnivariateStatistic` interface.
AggregateSummaryStatistics | An aggregator for `SummaryStatistics` from several data sets or data set partitions.
AggregateSummaryStatistics.AggregatingSummaryStatistics | A SummaryStatistics that also forwards all values added to it to a second `SummaryStatistics` for aggregation.
DescriptiveStatistics | Maintains a dataset of values of a single variable and computes descriptive statistics based on stored data.
MultivariateSummaryStatistics | Computes summary statistics for a stream of n-tuples added using the `addValue` method.
StatisticalSummaryValues | Value object representing the results of a univariate statistical summary.
SummaryStatistics | Computes summary statistics for a stream of data values added using the `addValue` method.
SynchronizedDescriptiveStatistics | Implementation of `DescriptiveStatistics` that is safe to use in a multithreaded environment.
SynchronizedMultivariateSummaryStatistics | Implementation of `MultivariateSummaryStatistics` that is safe to use in a multithreaded environment.
SynchronizedSummaryStatistics | Implementation of `SummaryStatistics` that is safe to use in a multithreaded environment.

## Package org.apache.commons.math3.stat.descriptive Description

Generic univariate summary statistic objects.

### UnivariateStatistic API Usage Examples:

#### UnivariateStatistic:

`/∗ evaluation approach ∗/
double[] values = new double[] { 1, 2, 3, 4, 5 };
UnivariateStatistic stat = new Mean();
out.println("mean = " + stat.evaluate(values));
`

#### StorelessUnivariateStatistic:

`/∗ incremental approach ∗/
double[] values = new double[] { 1, 2, 3, 4, 5 };
StorelessUnivariateStatistic stat = new Mean();
out.println("mean before adding a value is NaN = " + stat.getResult());
for (int i = 0; i < values.length; i++) {
stat.increment(values[i]);
out.println("current mean = " + stat2.getResult());
}
stat.clear();
out.println("mean after clear is NaN = " + stat.getResult());`