condition mean min max ZT0-3 14.799435 5.851005000000001 21.890349999999998 ZT4-7 5.85825 5.85825 5.85825 ZT8-11 7.111129999999999 7.111129999999999 7.111129999999999 ZT12-15 8.6615575 7.279764999999999 10.04335 ZT16-19 14.7833 14.7833 14.7833 ZT20-23 23.1634 23.1634 23.1634