condition mean min max ZT0-3 168.257588 168.257588 168.257588 ZT4-7 286.657808 286.657808 286.657808 ZT8-11 382.2025725 382.2025725 382.2025725 ZT12-15 460.92519649999997 460.92519649999997 460.92519649999997 ZT16-19 252.23783500000002 252.23783500000002 252.23783500000002 ZT20-23 143.79692749999998 143.79692749999998 143.79692749999998