condition mean min max ZT0-3 10.130171 10.130171 10.130171 ZT4-7 10.00647 10.00647 10.00647 ZT8-11 9.055284499999999 9.055284499999999 9.055284499999999 ZT12-15 7.737299999999999 7.737299999999999 7.737299999999999 ZT16-19 8.957333 8.957333 8.957333 ZT20-23 11.2335825 11.2335825 11.2335825