condition mean min max ZT0-3 0.8745831666666667 0.561791 1.077277 ZT4-7 1.213155 1.213155 1.213155 ZT8-11 3.47264 3.47264 3.47264 ZT12-15 2.8065875 2.686945 2.92623 ZT16-19 1.76472 1.76472 1.76472 ZT20-23 1.54123 1.54123 1.54123