condition mean min max ZT0-3 7.590071666666667 5.54954 9.766390000000001 ZT4-7 8.816135 8.816135 8.816135 ZT8-11 7.1416900000000005 7.1416900000000005 7.1416900000000005 ZT12-15 8.49146 7.503170000000001 9.47975 ZT16-19 6.86326 6.86326 6.86326 ZT20-23 10.6494 10.6494 10.6494