com.numericalmethod.suanshu.stats.descriptive.moment
Class Mean

java.lang.Object
  com.numericalmethod.suanshu.stats.descriptive.moment.Mean

All Implemented Interfaces:

Statistic

public class Mean
extends java.lang.Object
implements Statistic

The mean of a sample is the sum of all numbers in the sample, divided by the sample size.

 E(X) = Σ (xi) / N
 

This implementation supports incremental update of the statistic.

The R equivalent function is mean.

Constructor Summary

Mean()
Construct an empty Mean calculator.

Mean(double[] data)
Construct a Mean calculator, initialized with a sample.

Mean(Mean that)
Copy constructor.

Method Summary

void	addData(double... data) Recompute the statistic, incrementally if possible.
long	N() Get the size of the sample.
java.lang.String	toString()
double	value() Get the value of the statistic.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Mean

public Mean()

Construct an empty Mean calculator.

Mean

public Mean(double[] data)

Construct a Mean calculator, initialized with a sample.

Parameters:

data - a sample

Mean

public Mean(Mean that)

Copy constructor.

Parameters:

that - another Mean object

Method Detail

addData

public void addData(double... data)

Description copied from interface: Statistic

Recompute the statistic, incrementally if possible.

Specified by:

addData in interface Statistic

Parameters:

data - an array of new items

value

public double value()

Description copied from interface: Statistic

Get the value of the statistic.

Specified by:

value in interface Statistic

Returns:

the statistic

N

public long N()

Description copied from interface: Statistic

Get the size of the sample.

Specified by:

N in interface Statistic

Returns:

the sample size

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object