condition mean min max ZT0-3 18.8414 18.8414 18.8414 ZT4-7 13.831050000000001 13.831050000000001 13.831050000000001 ZT8-11 15.827200000000001 15.827200000000001 15.827200000000001 ZT12-15 19.0226 19.0226 19.0226 ZT16-19 18.9162 18.9162 18.9162 ZT20-23 21.023200000000003 21.023200000000003 21.023200000000003