condition mean min max ZT0-3 4.63402 2.9714799999999997 5.661045 ZT4-7 2.86562 2.86562 2.86562 ZT8-11 3.535225 3.535225 3.535225 ZT12-15 4.400862500000001 4.3188200000000005 4.482905 ZT16-19 4.5382750000000005 4.5382750000000005 4.5382750000000005 ZT20-23 5.64096 5.64096 5.64096