condition mean min max ZT0-3 2.5014950000000002 2.5014950000000002 2.5014950000000002 ZT4-7 1.717465 1.717465 1.717465 ZT8-11 2.5744100000000003 2.5744100000000003 2.5744100000000003 ZT12-15 4.189159999999999 4.189159999999999 4.189159999999999 ZT16-19 3.9262550000000003 3.9262550000000003 3.9262550000000003 ZT20-23 2.61723 2.61723 2.61723