/**
* __construct Function
*
* Constructor function for this regression model. Takes two arrays
* of data that are parallel arrays of independent and dependent
* observations.
*
* @param array $datax The series of independent variables
* @param array $datay The series of dependent variables
* @param BasicStats $stats instance of basic stats
* @return LinearRegression An object representing the regression model
*/
public function __construct(array $datax, array $datay, BasicStats $stats)
{
$this->beta = $stats->covariance($datax, $datay) / $stats->variance($datax);
$this->alpha = $stats->average($datay) - $this->beta * $stats->average($datax);
$this->r = $stats->correlation($datax, $datay);
parent::__construct($datax, $datay, $stats);
}
/**
* __construct Function
*
* Constructor function for this regression model. Takes two arrays
* of data that are parallel arrays of independent and dependent
* observations.
*
* @param array $datax The series of independent variables
* @param array $datay The series of dependent variables
* @param BasicStats $stats instance of basic stats
* @return LogarithmicRegression An object representing the regression model
*/
public function __construct($datax, $datay, BasicStats $stats)
{
$logx = array();
foreach ($datax as $x) {
$logx[] = log($x);
}
$this->r = $stats->correlation($logx, $datay);
$this->beta = $stats->covariance($logx, $datay) / $stats->variance($logx);
$this->alpha = $stats->average($datay) - $this->beta * $stats->average($logx);
parent::__construct($datax, $datay, $stats);
}
/**
* __construct Function
*
* Constructor function for this regression model. Takes two arrays
* of data that are parallel arrays of independent and dependent
* observations.
*
* @param array $datax The series of independent variables
* @param array $datay The series of dependent variables
* @param BasicStats $stats instance of basic stats
* @return ExponentialRegression An object representing the regression model
*/
public function __construct(array $datax, array $datay, BasicStats $stats)
{
$logy = array();
foreach ($datay as $y) {
$logy[] = log($y);
}
$this->r = $stats->correlation($datax, $logy);
$logbeta = $stats->covariance($datax, $logy) / $stats->variance($datax);
$logalpha = $stats->average($logy) - $logbeta * $stats->average($datax);
$this->beta = exp($logbeta);
$this->alpha = exp($logalpha);
parent::__construct($datax, $datay, $stats);
}
