condition mean min max ZT0-3 6.637205 4.78158 10.063865 ZT4-7 3.679965 3.679965 3.679965 ZT8-11 2.7904600000000004 2.7904600000000004 2.7904600000000004 ZT12-15 3.4141 1.832145 4.996055 ZT16-19 2.1906499999999998 2.1906499999999998 2.1906499999999998 ZT20-23 3.7080200000000003 3.7080200000000003 3.7080200000000003