public function __construct(array $samples, array $stats = [])
{
if (count($samples) < 1) {
throw new \LogicException('Cannot create a distribution with zero samples.');
}
$this->samples = $samples;
$this->closures = ['min' => function () {
return min($this->samples);
}, 'max' => function () {
return max($this->samples);
}, 'sum' => function () {
return array_sum($this->samples);
}, 'stdev' => function () {
return Statistics::stdev($this->samples);
}, 'mean' => function () {
return Statistics::mean($this->samples);
}, 'mode' => function () {
return Statistics::kdeMode($this->samples);
}, 'variance' => function () {
return Statistics::variance($this->samples);
}, 'rstdev' => function () {
$mean = $this->getMean();
return $mean ? $this->getStdev() / $mean * 100 : 0;
}];
if ($diff = array_diff(array_keys($stats), array_keys($this->closures))) {
throw new \RuntimeException(sprintf('Unknown pre-computed stat(s) encountered: "%s"', implode('", "', $diff)));
}
$this->stats = $stats;
}
public function testMean()
{
$stats = new Statistics();
$sets = $this->getSetData();
foreach ($sets as $name => $data) {
$stats->set($name, $data['set']);
$this->assertEquals($data['mean'], $stats->mean($name), 'Set ' . $name . ' mean()');
}
}
public function testMean()
{
//
// Integers
//
$values = [1, 2, 3, 4, 4];
$result = Statistics::mean($values);
$expected = 2.8;
$this->assertIdentical($expected, $result);
//
// Floats
//
$values = [-1.0, 2.5, 3.25, 5.75];
$result = Statistics::mean($values);
$expected = 2.625;
$this->assertIdentical($expected, $result);
//
// Mixed
//
$values = [-2, 2.5, 3.25, 5.75, 0];
$result = Statistics::mean($values);
$expected = 1.9;
$this->assertIdentical($expected, $result);
}
