condition mean min max ZT0-3 13.787884 13.787884 13.787884 ZT4-7 12.077395 12.077395 12.077395 ZT8-11 13.617455 13.617455 13.617455 ZT12-15 14.711929 14.711929 14.711929 ZT16-19 14.2167085 14.2167085 14.2167085 ZT20-23 12.098479 12.098479 12.098479