condition mean min max ZT0-3 8.4411875 8.360795 8.52158 ZT4-7 6.674715 6.674715 6.674715 ZT8-11 8.825395 8.825395 8.825395 ZT12-15 0 0 0 ZT16-19 9.428450000000002 9.428450000000002 9.428450000000002 ZT20-23 7.929515 7.929515 7.929515