I believe it is a logic error.

The code in the while block does not execute because the while condition is false.

$average = 3;
$i = 0;
while ($i > 0 and $i <= $average)
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In order for the while condition to be true, $i must be either 1, 2 or 3. But $i starts at 0.

Do you really want this?

while ($i >= 0 and $i <= $average)
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