condition mean min max ZT0-3 19.698318 19.698318 19.698318 ZT4-7 18.974137499999998 18.974137499999998 18.974137499999998 ZT8-11 19.449253499999998 19.449253499999998 19.449253499999998 ZT12-15 17.007202500000002 17.007202500000002 17.007202500000002 ZT16-19 18.043305500000002 18.043305500000002 18.043305500000002 ZT20-23 18.974314 18.974314 18.974314