condition mean min max ZT0-3 11.037488333333334 9.979415 12.2163 ZT4-7 8.129215 8.129215 8.129215 ZT8-11 8.707094999999999 8.707094999999999 8.707094999999999 ZT12-15 9.694685 9.504985 9.884385 ZT16-19 11.195 11.195 11.195 ZT20-23 9.315115 9.315115 9.315115