condition mean min max ZT0-3 5.472221666666667 3.358135 6.80919 ZT4-7 4.66903 4.66903 4.66903 ZT8-11 4.707015 4.707015 4.707015 ZT12-15 5.153575 3.9577400000000003 6.34941 ZT16-19 5.326124999999999 5.326124999999999 5.326124999999999 ZT20-23 8.229849999999999 8.229849999999999 8.229849999999999