condition mean min max ZT0-3 4.699422500000001 4.22301 5.175835 ZT4-7 6.04708 6.04708 6.04708 ZT8-11 6.7684 6.7684 6.7684 ZT12-15 0 0 0 ZT16-19 7.682365 7.682365 7.682365 ZT20-23 6.5634 6.5634 6.5634