condition mean min max ZT0-3 2.3857566666666665 2.3857566666666665 2.3857566666666665 ZT4-7 2.4673049999999996 2.4673049999999996 2.4673049999999996 ZT8-11 1.5355150000000002 1.5355150000000002 1.5355150000000002 ZT12-15 2.159825 2.159825 2.159825 ZT16-19 2.67583 2.67583 2.67583 ZT20-23 2.46773 2.46773 2.46773