condition mean min max ZT0-3 5.175478333333333 4.27147 6.167439999999999 ZT4-7 4.742710000000001 4.742710000000001 4.742710000000001 ZT8-11 3.5658250000000002 3.5658250000000002 3.5658250000000002 ZT12-15 7.3141475 7.19585 7.4324449999999995 ZT16-19 7.780515 7.780515 7.780515 ZT20-23 8.155465 8.155465 8.155465