condition mean min max ZT0-3 7.582688 7.582688 7.582688 ZT4-7 8.6840725 8.6840725 8.6840725 ZT8-11 10.0194065 10.0194065 10.0194065 ZT12-15 9.448412000000001 9.448412000000001 9.448412000000001 ZT16-19 8.9979645 8.9979645 8.9979645 ZT20-23 8.759771 8.759771 8.759771