condition mean min max ZT0-3 1.5785866666666668 1.521285 1.682665 ZT4-7 1.5884865000000001 1.5884865000000001 1.5884865000000001 ZT8-11 1.65419 1.65419 1.65419 ZT12-15 2.7852025 2.57521 2.995195 ZT16-19 2.581855 2.581855 2.581855 ZT20-23 2.61666 2.61666 2.61666