condition mean min max ZT0-3 3.7657149999999997 2.86496 5.33986 ZT4-7 2.023855 2.023855 2.023855 ZT8-11 3.9585150000000002 3.9585150000000002 3.9585150000000002 ZT12-15 3.5325024999999997 3.1056749999999997 3.95933 ZT16-19 3.9253050000000003 3.9253050000000003 3.9253050000000003 ZT20-23 4.954235000000001 4.954235000000001 4.954235000000001