condition mean min max ZT0-3 7.802975 7.802975 7.802975 ZT4-7 7.31939 7.31939 7.31939 ZT8-11 4.4494050000000005 4.4494050000000005 4.4494050000000005 ZT12-15 4.543945 4.543945 4.543945 ZT16-19 6.436909999999999 6.436909999999999 6.436909999999999 ZT20-23 8.81306 8.81306 8.81306