/**
* Make the z-transform of averages of the cities
* @param array $munAverages
* @return Return a array with the z value of each city
*/
public function zTransformation($munAverages)
{
//make average of given cities' averages
$sumAvg = 0;
$avg = 0;
foreach ($munAverages as $key => $value) {
$sumAvg += $value;
}
$avg = $sumAvg / sizeof($munAverages);
//Calculate Standard Deviation
$std = ZtransformController::standarDeviation($munAverages, $avg);
//Apply the z-transform and save the results in an array
$zValues = array();
//keep the z-transform results
$zTransform = 0;
foreach ($munAverages as $key => $value) {
$zTransform = ($value - $avg) / $std;
$zValues = array_merge($zValues, array($key => $zTransform));
}
return $zValues;
}
