public class Variance extends Object implements Statistic
Var(X) = E[(X - E(X))2]This implementation uses Chan's update formula to incrementally compute the new statistic. The R equivalent function is
var.| Constructor and Description |
|---|
Variance()
Construct an empty
Variance calculator. |
Variance(double[] data)
Construct an unbiased
Variance calculator. |
Variance(double[] data,
boolean unbiased)
Construct a
Variance calculator,
initialized with a sample. |
Variance(Variance that)
Copy constructor.
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| Modifier and Type | Method and Description |
|---|---|
void |
addData(double... data)
Recompute the statistic with more data, incrementally if possible.
|
double |
mean()
Get the sample mean.
|
long |
N()
Get the size of the sample.
|
double |
standardDeviation()
Get the standard deviation of the sample,
which is the square root of the variance.
|
String |
toString() |
double |
value()
Get the value of the statistic.
|
public Variance()
Variance calculator.public Variance(double[] data,
boolean unbiased)
Variance calculator,
initialized with a sample.data - a sampleunbiased - true if the variance calculation uses the unbiased formulapublic Variance(double[] data)
Variance calculator.data - a samplepublic Variance(Variance that)
that - a Variance calculatorpublic double standardDeviation()
public void addData(double... data)
Statisticpublic double value()
Statisticpublic double mean()
public long N()
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