condition mean min max ZT0-3 5.307728333333333 3.4243750000000004 7.755575 ZT4-7 10.157855000000001 10.157855000000001 10.157855000000001 ZT8-11 9.50939 9.50939 9.50939 ZT12-15 7.3510575 5.92725 8.774865 ZT16-19 4.00027 4.00027 4.00027 ZT20-23 4.681825 4.681825 4.681825