seems that thorpe provided the response that i was going to,
so I will explain what went wrong. The code that you have,
$i = 1;
while ($i <= $Quantity){
$output = array(rand($RandLow, $RandHigh));
$i++;
}
print_r($output);
rewrites your $ouput variable to an array with only one value every iteration.. what needs to be done, as thorpe illustrated, is instead of declaring your array inside of your loop, which will result in the array being rewritten every iteration, you need to declare an empty array before your loop and then add to the array inside of your loop.