condition mean min max ZT0-3 20.7587 19.97795 21.539450000000002 ZT4-7 16.6062 16.6062 16.6062 ZT8-11 11.372715 11.372715 11.372715 ZT12-15 0 0 0 ZT16-19 23.016550000000002 23.016550000000002 23.016550000000002 ZT20-23 23.8199 23.8199 23.8199