condition mean min max ZT0-3 3.827755 3.779455 3.876055 ZT4-7 2.74788 2.74788 2.74788 ZT8-11 4.598075 4.598075 4.598075 ZT12-15 0 0 0 ZT16-19 4.35442 4.35442 4.35442 ZT20-23 4.487025 4.487025 4.487025