condition mean min max ZT0-3 5.054665 5.054665 5.054665 ZT4-7 4.090625 4.090625 4.090625 ZT8-11 3.171605 3.171605 3.171605 ZT12-15 3.379085 3.379085 3.379085 ZT16-19 3.9037949999999997 3.9037949999999997 3.9037949999999997 ZT20-23 4.59281 4.59281 4.59281