condition mean min max ZT0-3 17.234299 17.234299 17.234299 ZT4-7 28.0539035 28.0539035 28.0539035 ZT8-11 42.0863315 42.0863315 42.0863315 ZT12-15 19.537036 19.537036 19.537036 ZT16-19 21.831027 21.831027 21.831027 ZT20-23 17.277943 17.277943 17.277943