condition mean min max ZT0-3 5.699999999999999 5.699999999999999 5.699999999999999 ZT4-7 6.5 6.5 6.5 ZT8-11 20.1 20.1 20.1 ZT12-15 7.8 7.8 7.8 ZT16-19 26.599999999999998 26.599999999999998 26.599999999999998 ZT20-23 5.7 5.7 5.7