condition mean min max ZT0-3 4.608085 4.608085 4.608085 ZT4-7 2.961295 2.961295 2.961295 ZT8-11 5.7619299999999996 5.7619299999999996 5.7619299999999996 ZT12-15 4.6699150000000005 4.6699150000000005 4.6699150000000005 ZT16-19 4.08353 4.08353 4.08353 ZT20-23 2.63747 2.63747 2.63747