condition mean min max ZT0-3 3.6562475 3.03669 4.275805 ZT4-7 2.8645500000000004 2.8645500000000004 2.8645500000000004 ZT8-11 9.657285 9.657285 9.657285 ZT12-15 0 0 0 ZT16-19 7.6367650000000005 7.6367650000000005 7.6367650000000005 ZT20-23 5.102885 5.102885 5.102885