condition mean min max ZT0-3 3.5018716666666667 3.2429949999999996 3.8596250000000003 ZT4-7 3.06611 3.06611 3.06611 ZT8-11 2.81287 2.81287 2.81287 ZT12-15 3.8281899999999998 3.7711949999999996 3.885185 ZT16-19 2.6622250000000003 2.6622250000000003 2.6622250000000003 ZT20-23 3.4194500000000003 3.4194500000000003 3.4194500000000003