condition mean min max ZT0-3 28.253125 25.5396 30.96665 ZT4-7 12.6456 12.6456 12.6456 ZT8-11 13.015 13.015 13.015 ZT12-15 0 0 0 ZT16-19 20.222099999999998 20.222099999999998 20.222099999999998 ZT20-23 24.84735 24.84735 24.84735