condition mean min max ZT0-3 2.0708913333333334 1.109364 3.24872 ZT4-7 5.1810849999999995 5.1810849999999995 5.1810849999999995 ZT8-11 16.136200000000002 16.136200000000002 16.136200000000002 ZT12-15 8.105442499999999 6.21411 9.996775 ZT16-19 4.374665 4.374665 4.374665 ZT20-23 0.21014952650000002 0.21014952650000002 0.21014952650000002