condition mean min max ZT0-3 3.240425 3.240425 3.240425 ZT4-7 3.11246 3.11246 3.11246 ZT8-11 2.386985 2.386985 2.386985 ZT12-15 2.692125 2.692125 2.692125 ZT16-19 3.6345 3.6345 3.6345 ZT20-23 2.69977 2.69977 2.69977