condition mean min max ZT0-3 14.264041666666667 10.653325 16.29665 ZT4-7 15.645299999999999 15.645299999999999 15.645299999999999 ZT8-11 20.8916 20.8916 20.8916 ZT12-15 21.032325 19.52365 22.541 ZT16-19 17.61655 17.61655 17.61655 ZT20-23 23.20205 23.20205 23.20205