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java.lang.Objectorg.apache.commons.math.stat.inference.OneWayAnovaImpl
public class OneWayAnovaImpl
Implements one-way ANOVA statistics defined in the OneWayAnovaImpl
interface.
Uses the
commons-math F Distribution implementation to estimate exact p-values.
This implementation is based on a description at http://faculty.vassar.edu/lowry/ch13pt1.html
Abbreviations: bg = between groups,
wg = within groups,
ss = sum squared deviations
| Constructor Summary | |
|---|---|
OneWayAnovaImpl()
Default constructor. |
|
| Method Summary | |
|---|---|
double |
anovaFValue(Collection<double[]> categoryData)
Computes the ANOVA F-value for a collection of double[]
arrays. |
double |
anovaPValue(Collection<double[]> categoryData)
Computes the ANOVA P-value for a collection of double[]
arrays. |
boolean |
anovaTest(Collection<double[]> categoryData,
double alpha)
Performs an ANOVA test, evaluating the null hypothesis that there is no difference among the means of the data categories. |
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
|---|
public OneWayAnovaImpl()
| Method Detail |
|---|
public double anovaFValue(Collection<double[]> categoryData)
throws IllegalArgumentException,
MathException
double[]
arrays.
Preconditions:
Collection must contain
double[] arrays.double[] arrays in the
categoryData collection and each of these arrays must
contain at least two values.This implementation computes the F statistic using the definitional formula
F = msbg/mswgwhere
msbg = between group mean square mswg = within group mean squareare as defined here
anovaFValue in interface OneWayAnovacategoryData - Collection of double[]
arrays each containing data for one category
IllegalArgumentException - if the preconditions are not met
MathException - if the statistic can not be computed do to a
convergence or other numerical error.
public double anovaPValue(Collection<double[]> categoryData)
throws IllegalArgumentException,
MathException
double[]
arrays.
Preconditions:
Collection must contain
double[] arrays.double[] arrays in the
categoryData collection and each of these arrays must
contain at least two values.
This implementation uses the
commons-math F Distribution implementation to estimate the exact
p-value, using the formula
p = 1 - cumulativeProbability(F)where
F is the F value and cumulativeProbability
is the commons-math implementation of the F distribution.
anovaPValue in interface OneWayAnovacategoryData - Collection of double[]
arrays each containing data for one category
IllegalArgumentException - if the preconditions are not met
MathException - if the statistic can not be computed do to a
convergence or other numerical error.
public boolean anovaTest(Collection<double[]> categoryData,
double alpha)
throws IllegalArgumentException,
MathException
Preconditions:
Collection must contain
double[] arrays.double[] arrays in the
categoryData collection and each of these arrays must
contain at least two values.
This implementation uses the
commons-math F Distribution implementation to estimate the exact
p-value, using the formula
p = 1 - cumulativeProbability(F)where
F is the F value and cumulativeProbability
is the commons-math implementation of the F distribution.
True is returned iff the estimated p-value is less than alpha.
anovaTest in interface OneWayAnovacategoryData - Collection of double[]
arrays each containing data for one categoryalpha - significance level of the test
IllegalArgumentException - if the preconditions are not met
MathException - if the statistic can not be computed do to a
convergence or other numerical error.
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