condition mean min max ZT0-3 2.894845 2.894845 2.894845 ZT4-7 1.0326749999999998 1.0326749999999998 1.0326749999999998 ZT8-11 2.42726 2.42726 2.42726 ZT12-15 6.6792750000000005 6.6792750000000005 6.6792750000000005 ZT16-19 6.773345 6.773345 6.773345 ZT20-23 3.75939 3.75939 3.75939