condition mean min max ZT0-3 11.581195481249999 11.2241050425 11.93828592 ZT4-7 6.6956405055 6.497528634 6.893752377 ZT8-11 10.01495864975 8.337135421 11.6927818785 ZT12-15 11.2965267345 9.859091354 12.733962115 ZT16-19 13.903862005 13.214844575 14.592879435 ZT20-23 18.233619095 17.48741091 18.979827280000002