condition mean min max ZT0-3 9.0121425 8.677620000000001 9.346665 ZT4-7 9.316015 9.316015 9.316015 ZT8-11 13.1318 13.1318 13.1318 ZT12-15 0 0 0 ZT16-19 18.03 18.03 18.03 ZT20-23 14.393 14.393 14.393