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Class weka.core.Statistics
java.lang.Object
|
+----weka.core.Statistics
- public class Statistics
- extends java.lang.Object
Class implementing some distributions, tests, etc. Most of the
code is adapted from Gary Perlman's unixstat.
- Version:
- $Revision: 1.4 $
- Author:
- Eibe Frank (eibe@cs.waikato.ac.nz)
Statistics()
-
binomialStandardError(double, int)
- Computes standard error for observed values of a binomial
random variable.
chiSquaredProbability(double, int)
- Returns chi-squared probability for given value and degrees
of freedom.
FCriticalValue(double, int, int)
- Critical value for given probability of F-distribution.
FProbability(double, int, int)
- Computes probability of F-ratio.
main(String[])
- Main method for testing this class.
normalProbability(double)
- Returns probability that the standardized normal variate Z (mean = 0, standard
deviation = 1) is less than z.
studentTConfidenceInterval(int, double, double)
- Computes absolute size of half of a student-t confidence interval
for given degrees of freedom, probability, and observed value.
Statistics
public Statistics()
binomialStandardError
public static double binomialStandardError(double p,
int n)
Computes standard error for observed values of a binomial
random variable.
- Parameters:
p
- the probability of success
n
- the size of the sample
- Returns:
- the standard error
chiSquaredProbability
public static double chiSquaredProbability(double x,
int df)
Returns chi-squared probability for given value and degrees
of freedom. (The probability that the chi-squared variate
will be greater than x for the given degrees of freedom.)
Adapted from unixstat by Gary Perlman.
- Parameters:
x
- the value
df
- the number of degrees of freedom
FCriticalValue
public static double FCriticalValue(double p,
int df1,
int df2)
Critical value for given probability of F-distribution.
Adapted from unixstat by Gary Perlman.
- Parameters:
p
- the probability
df1
- the first number of degrees of freedom
df2
- the second number of degrees of freedom
- Returns:
- the critical value for the given probability
FProbability
public static double FProbability(double F,
int df1,
int df2)
Computes probability of F-ratio.
Adapted from unixstat by Gary Perlman.
Collected Algorithms of the CACM
Algorithm 322
Egon Dorrer
- Parameters:
F
- the F-ratio
df1
- the first number of degrees of freedom
df2
- the second number of degrees of freedom
- Returns:
- the probability of the F-ratio.
normalProbability
public static double normalProbability(double z)
Returns probability that the standardized normal variate Z (mean = 0, standard
deviation = 1) is less than z.
Adapted from unixstat by Gary Perlman.
- Parameters:
the
- z-value
- Returns:
- the probability of the z value according to the normal pdf
studentTConfidenceInterval
public static double studentTConfidenceInterval(int df,
double p,
double se)
Computes absolute size of half of a student-t confidence interval
for given degrees of freedom, probability, and observed value.
- Parameters:
df
- the number of degrees of freedom
p
- the probability
se
- the observed value
- Returns:
- absolute size of half of a student-t confidence interval
main
public static void main(java.lang.String ops[])
Main method for testing this class.
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