condition mean min max ZT0-3 6.76081 6.76081 6.76081 ZT4-7 4.80563 4.80563 4.80563 ZT8-11 5.649395 5.649395 5.649395 ZT12-15 6.2943999999999996 6.2943999999999996 6.2943999999999996 ZT16-19 7.938945 7.938945 7.938945 ZT20-23 7.32881 7.32881 7.32881