Float is ignored

<?php
$coinMultipliers = array('1' => 12, '2' => 12, '3' => 12, '4' => 10, '5' => 10, '6' => 8, '7' => 8, '8' => 6, '10' => 6, '14' => 5, '16' => 4, '18' => 3, '20' => 2, '25' => 1, '30' => 0.7, '150' => 0.3);

function getRandomCoinMultiplier(array $weightedValues)
{
    $rand = mt_rand(1, (int) array_sum($weightedValues));

    foreach ($weightedValues as $key => $value) {
        $rand -= $value;
        if ($rand <= 0) {
            return $key;
        }
    }
}

// The following FOR-LOOP prints "nothing" when the random selection from above
// is a FLOAT value.
for ($i = 0; $i < 1000; $i++) {
    echo getRandomCoinMultiplier($coinMultipliers)."\r\n";
}