condition mean min max ZT0-3 8.5129925 7.992535 9.033449999999998 ZT4-7 8.283725 8.283725 8.283725 ZT8-11 5.74483 5.74483 5.74483 ZT12-15 0 0 0 ZT16-19 6.679065 6.679065 6.679065 ZT20-23 8.546405 8.546405 8.546405