condition mean min max ZT0-3 20.72005 19.38675 22.053350000000002 ZT4-7 25.1387 25.1387 25.1387 ZT8-11 19.446150000000003 19.446150000000003 19.446150000000003 ZT12-15 0 0 0 ZT16-19 21.410899999999998 21.410899999999998 21.410899999999998 ZT20-23 29.81 29.81 29.81