condition mean min max ZT0-3 7.4688875 6.50597 8.431805 ZT4-7 7.4059 7.4059 7.4059 ZT8-11 6.911965 6.911965 6.911965 ZT12-15 0 0 0 ZT16-19 9.232875 9.232875 9.232875 ZT20-23 6.8333200000000005 6.8333200000000005 6.8333200000000005