condition mean min max ZT0-3 8.7867475 7.865985 9.70751 ZT4-7 6.574960000000001 6.574960000000001 6.574960000000001 ZT8-11 7.35968 7.35968 7.35968 ZT12-15 0 0 0 ZT16-19 9.415075 9.415075 9.415075 ZT20-23 8.760515000000002 8.760515000000002 8.760515000000002