condition mean min max ZT0-3 405.352888 405.352888 405.352888 ZT4-7 578.014821 578.014821 578.014821 ZT8-11 291.73895600000003 291.73895600000003 291.73895600000003 ZT12-15 250.8509995 250.8509995 250.8509995 ZT16-19 255.79437049999999 255.79437049999999 255.79437049999999 ZT20-23 311.283102 311.283102 311.283102