condition mean min max ZT0-3 59.444428 59.444428 59.444428 ZT4-7 60.9945525 60.9945525 60.9945525 ZT8-11 61.7926345 61.7926345 61.7926345 ZT12-15 83.57332500000001 83.57332500000001 83.57332500000001 ZT16-19 110.88071500000001 110.88071500000001 110.88071500000001 ZT20-23 117.313436 117.313436 117.313436