condition mean min max ZT0-3 4.4429316666666665 3.3902200000000002 5.11465 ZT4-7 3.6928400000000003 3.6928400000000003 3.6928400000000003 ZT8-11 4.98135 4.98135 4.98135 ZT12-15 5.764925 5.4196550000000006 6.110194999999999 ZT16-19 7.3121 7.3121 7.3121 ZT20-23 8.77703 8.77703 8.77703