condition mean min max ZT0-3 1.9434155 1.5253165000000002 2.219855 ZT4-7 2.44209 2.44209 2.44209 ZT8-11 2.1087350000000002 2.1087350000000002 2.1087350000000002 ZT12-15 4.734045 4.1183 5.3497900000000005 ZT16-19 3.7576650000000003 3.7576650000000003 3.7576650000000003 ZT20-23 3.6387099999999997 3.6387099999999997 3.6387099999999997