condition mean min max ZT0-3 4.205475 4.078145 4.3328050000000005 ZT4-7 4.07276 4.07276 4.07276 ZT8-11 5.618455 5.618455 5.618455 ZT12-15 0 0 0 ZT16-19 9.007735 9.007735 9.007735 ZT20-23 7.00881 7.00881 7.00881