condition mean min max ZT0-3 4.101826666666667 3.670045 4.69727 ZT4-7 4.91841 4.91841 4.91841 ZT8-11 5.47234 5.47234 5.47234 ZT12-15 6.81564 5.8115000000000006 7.81978 ZT16-19 7.25035 7.25035 7.25035 ZT20-23 5.955835 5.955835 5.955835