condition mean min max ZT0-3 6.729481666666667 5.965515 7.429795 ZT4-7 5.1423000000000005 5.1423000000000005 5.1423000000000005 ZT8-11 6.416235 6.416235 6.416235 ZT12-15 10.463625 10.18905 10.738199999999999 ZT16-19 8.657615 8.657615 8.657615 ZT20-23 8.743195 8.743195 8.743195