condition mean min max ZT0-3 17.213733333333334 13.415 19.40565 ZT4-7 14.486650000000001 14.486650000000001 14.486650000000001 ZT8-11 11.9398 11.9398 11.9398 ZT12-15 15.2144 15.0562 15.372599999999998 ZT16-19 20.658450000000002 20.658450000000002 20.658450000000002 ZT20-23 21.33565 21.33565 21.33565