condition mean min max ZT0-3 27.493836666666667 8.53626 37.57355 ZT4-7 6.0059 6.0059 6.0059 ZT8-11 12.033100000000001 12.033100000000001 12.033100000000001 ZT12-15 19.591525 15.4125 23.77055 ZT16-19 39.069599999999994 39.069599999999994 39.069599999999994 ZT20-23 60.935900000000004 60.935900000000004 60.935900000000004