function calculateMean($data) {
if (count($data) === 0) {
return 0.0;
}
$sum = array_sum($data);
return $sum / count($data);
}
function calculateStandardDeviation($data, $mean) {
$n = count($data);
if ($n < 2) {
return 0.0;
}
$sumOfSquaredDiffs = 0.0;
foreach ($data as $value) {
$diff = $value - $mean;
$sumOfSquaredDiffs += $diff * $diff;
}
$variance = $sumOfSquaredDiffs / ($n - 1); // Sample standard deviation
return sqrt($variance);
}
$numbers = [3.4, 1.8, 4.3, 5.0, 6.2];
$mean = calculateMean($numbers);
$stddev = calculateStandardDeviation($numbers, $mean);
printf("Mean: %.2f\n", $mean);
printf("Standard Deviation: %.2f\n", $stddev);
/*
run:
Mean: 4.14
Standard Deviation: 1.66
*/
