condition mean min max ZT0-3 8.02463 8.02463 8.02463 ZT4-7 6.290165 6.290165 6.290165 ZT8-11 8.009575 8.009575 8.009575 ZT12-15 9.79449 9.79449 9.79449 ZT16-19 11.6603 11.6603 11.6603 ZT20-23 8.4266 8.4266 8.4266