condition mean min max ZT0-3 8.11051 8.11051 8.11051 ZT4-7 9.010144 9.010144 9.010144 ZT8-11 9.331319 9.331319 9.331319 ZT12-15 8.2670445 8.2670445 8.2670445 ZT16-19 8.4537285 8.4537285 8.4537285 ZT20-23 9.3998875 9.3998875 9.3998875