condition mean min max ZT0-3 6.699999999999999 6.699999999999999 6.699999999999999 ZT4-7 5.5 5.5 5.5 ZT8-11 20.25 20.25 20.25 ZT12-15 5.85 5.85 5.85 ZT16-19 5.4 5.4 5.4 ZT20-23 11.950000000000001 11.950000000000001 11.950000000000001