SourcePro® API Reference Guide

 
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RWLinearRegressionFTest Class Reference

Tests that the estimated parameters in a linear regression model are equal to a hypothesized vector of values. More...

#include <rw/analytics/lrftest.h>

Public Member Functions

 RWLinearRegressionFTest ()
 
 RWLinearRegressionFTest (const RWLinearRegressionFTest &t)
 
 RWLinearRegressionFTest (const RWLinearRegression &lr)
 
 RWLinearRegressionFTest (const RWLinearRegression &lr, const RWGenMat< double > &A, const RWMathVec< double > &c)
 
double criticalValue (double alpha) const
 
double FStatisticPValue () const
 
double FStatisticValue () const
 
RWLinearRegressionFTestoperator= (const RWLinearRegressionFTest &ft)
 
bool reject (double alpha=.05) const
 
void setHypothesis (const RWGenMat< double > &A, const RWMathVec< double > &c)
 
void setLinearRegression (const RWLinearRegression &lr)
 

Detailed Description

Class RWLinearRegressionFTest can be used to test that the estimated parameters in a linear regression model are equal to a hypothesized vector of values. For example, it can test the hypothesis that all parameters are equal to 0. To be completely precise, the class tests the hypothesis that the estimated parameters are the solution to some specified system of linear equations. The test is based on the F statistic, described in the section "Multiple Linear Regression," in the Business Analysis Module User's Guide.

Synopsis
#include <rw/math/genmat.h>
#include <rw/math/mathvec.h>
#include <rw/analytics/linregress.h>
#include <rw/analytics/lrftest.h>
RWGenMat<double> predictorMatrix;
RWMathVec<double> observationVector;
RWLinearRegression lr(predictorMatrix, observationVector);
Example

The following example creates a linear regression object and tests the hypothesis that all parameters are equal to 0 at a confidence level of 99 percent.

#include <rw/analytics/linregress.h>
#include <lrftest.h>
#include <iostream>
int main() {
RWGenMat<double> predictorMatrix =
"5x2 [1.2 2.1 8 7 3 3.2 6.4 4.6 2 2.3]";
RWMathVec<double> observationVector = "[2.5 3.7 1.4 2.3 5.6]";
RWLinearRegression lr(predictorMatrix, observationVector);
std::cout << " f statistic value: " << FTest.FStatisticValue()
<< std::endl;
std::cout << " f statistic P-value: " << FTest.FStatisticPValue()
<< std::endl;
std::cout << " 99% Critical value: " << FTest.criticalValue(0.01)
<< std::endl;
if ( FTest.reject(0.01) )
{
std::cout << "Reject H0 at significance level 0.01" << std::endl;
}
else
{
std::cout << "Fail to reject H0 at significance level 0.01"
<< std::endl;
}
return 0;
}

Constructor & Destructor Documentation

RWLinearRegressionFTest::RWLinearRegressionFTest ( )

Constructs an empty F test object. Behavior is undefined.

RWLinearRegressionFTest::RWLinearRegressionFTest ( const RWLinearRegressionFTest t)

Constructs a copy of t.

RWLinearRegressionFTest::RWLinearRegressionFTest ( const RWLinearRegression lr)

Constructs an F test for the hypothesis that \(\beta_1 = \beta_2 = ..\beta_p = 0\)

RWLinearRegressionFTest::RWLinearRegressionFTest ( const RWLinearRegression lr,
const RWGenMat< double > &  A,
const RWMathVec< double > &  c 
)

Constructs an F test for the hypothesis that \(A\beta = c\)

Member Function Documentation

double RWLinearRegressionFTest::criticalValue ( double  alpha) const
inline

Returns the critical value for the test at the significance level alpha.

double RWLinearRegressionFTest::FStatisticPValue ( ) const
inline

Returns the P-value for the test.

double RWLinearRegressionFTest::FStatisticValue ( ) const
inline

Returns the value of the F statistic.

RWLinearRegressionFTest& RWLinearRegressionFTest::operator= ( const RWLinearRegressionFTest ft)

Copies the contents of ft to self.

bool RWLinearRegressionFTest::reject ( double  alpha = .05) const
inline

Returns true if the hypothesis being tested will be rejected at the significance level alpha.

void RWLinearRegressionFTest::setHypothesis ( const RWGenMat< double > &  A,
const RWMathVec< double > &  c 
)

Sets the hypothesis being tested to \(A\beta = c\)

void RWLinearRegressionFTest::setLinearRegression ( const RWLinearRegression lr)

Sets the linear regression for which the hypothesis will be tested.

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