condition mean min max ZT0-3 4.04039 4.04039 4.04039 ZT4-7 1.647915 1.647915 1.647915 ZT8-11 6.2689 6.2689 6.2689 ZT12-15 23.70745 23.70745 23.70745 ZT16-19 17.3732 17.3732 17.3732 ZT20-23 7.53036 7.53036 7.53036