assertEquals(-0.641, Correlation::pearson($x, $y), '', $delta); //http://www.statisticshowto.com/how-to-compute-pearsons-correlation-coefficients/ $delta = 0.001; $x = [43, 21, 25, 42, 57, 59]; $y = [99, 65, 79, 75, 87, 82]; $this->assertEquals(0.549, Correlation::pearson($x, $y), '', $delta); $delta = 0.001; $x = [60, 61, 62, 63, 65]; $y = [3.1, 3.6, 3.8, 4, 4.1]; $this->assertEquals(0.911, Correlation::pearson($x, $y), '', $delta); } /** * @expectedException \Phpml\Exception\InvalidArgumentException */ public function testThrowExceptionOnInvalidArgumentsForPearsonCorrelation() { Correlation::pearson([1, 2, 4], [3, 5]); } }