condition mean min max ZT0-3 3.178491666666667 2.45915 3.7375350000000003 ZT4-7 4.090199999999999 4.090199999999999 4.090199999999999 ZT8-11 6.958445 6.958445 6.958445 ZT12-15 10.4722975 9.229045 11.71555 ZT16-19 7.237170000000001 7.237170000000001 7.237170000000001 ZT20-23 5.3118549999999995 5.3118549999999995 5.3118549999999995