condition mean min max ZT0-3 15.52785 15.52785 15.52785 ZT4-7 11.81435 11.81435 11.81435 ZT8-11 8.65433 8.65433 8.65433 ZT12-15 7.35718 7.35718 7.35718 ZT16-19 12.93895 12.93895 12.93895 ZT20-23 12.8616 12.8616 12.8616