condition mean min max ZT0-3 20.556800000000003 20.556800000000003 20.556800000000003 ZT4-7 16.685200000000002 16.685200000000002 16.685200000000002 ZT8-11 12.07325 12.07325 12.07325 ZT12-15 18.52705 18.52705 18.52705 ZT16-19 20.559 20.559 20.559 ZT20-23 20.22455 20.22455 20.22455