public function testEvaluate(array $points, $α, $λ, $yHat)
{
$loess = new LOESS($points, $α, $λ);
$test_yHat = $loess->yHat();
foreach ($test_yHat as $key => $value) {
$this->assertEquals($yHat[$key], $value, '', 1.0E-7);
}
}