condition mean min max ZT0-3 1.70733 1.5884900000000002 1.7757100000000001 ZT4-7 1.446135 1.446135 1.446135 ZT8-11 1.6684999999999999 1.6684999999999999 1.6684999999999999 ZT12-15 3.940195 3.908055 3.972335 ZT16-19 3.14248 3.14248 3.14248 ZT20-23 3.107875 3.107875 3.107875