condition mean min max ZT0-3 5.798895 4.635895 7.173170000000001 ZT4-7 3.43877 3.43877 3.43877 ZT8-11 4.5589 4.5589 4.5589 ZT12-15 4.5462525 3.7581949999999997 5.33431 ZT16-19 5.76893 5.76893 5.76893 ZT20-23 7.612055 7.612055 7.612055