condition mean min max ZT0-3 6.644195 6.644195 6.644195 ZT4-7 6.32064 6.32064 6.32064 ZT8-11 3.65699 3.65699 3.65699 ZT12-15 3.7556249999999998 3.7556249999999998 3.7556249999999998 ZT16-19 6.9828600000000005 6.9828600000000005 6.9828600000000005 ZT20-23 6.92927 6.92927 6.92927