condition mean min max ZT0-3 7.19577 7.19577 7.19577 ZT4-7 7.958500000000001 7.958500000000001 7.958500000000001 ZT8-11 7.8075399999999995 7.8075399999999995 7.8075399999999995 ZT12-15 7.977816666666667 7.977816666666667 7.977816666666667 ZT16-19 7.201510000000001 7.201510000000001 7.201510000000001 ZT20-23 7.0589 7.0589 7.0589