condition mean min max ZT0-3 1.7737308333333333 0.9418825000000001 2.3397949999999996 ZT4-7 1.6486450000000001 1.6486450000000001 1.6486450000000001 ZT8-11 1.774375 1.774375 1.774375 ZT12-15 3.6310974999999996 3.0802899999999998 4.1819049999999995 ZT16-19 2.70661 2.70661 2.70661 ZT20-23 2.48888 2.48888 2.48888