condition mean min max ZT0-3 6.578391627 6.088342433999999 7.06844082 ZT4-7 7.7830162957499995 6.657742585499999 8.908290006 ZT8-11 8.8607010065 8.5298612695 9.1915407435 ZT12-15 13.729826448999999 11.113622422999999 16.346030475 ZT16-19 22.424713675 19.75869383 25.09073352 ZT20-23 30.2227828675 28.53936075 31.906204985000002