condition mean min max ZT0-3 16.285139 16.285139 16.285139 ZT4-7 14.6521315 14.6521315 14.6521315 ZT8-11 12.572722500000001 12.572722500000001 12.572722500000001 ZT12-15 13.220886 13.220886 13.220886 ZT16-19 22.4680785 22.4680785 22.4680785 ZT20-23 37.068104 37.068104 37.068104