# 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.
  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());`

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