condition mean min max ZT0-3 2.199415 2.199415 2.199415 ZT4-7 1.9870999999999999 1.9870999999999999 1.9870999999999999 ZT8-11 1.221155 1.221155 1.221155 ZT12-15 1.22515 1.22515 1.22515 ZT16-19 2.55059 2.55059 2.55059 ZT20-23 1.7531750000000001 1.7531750000000001 1.7531750000000001