condition mean min max ZT0-3 11.176683333333333 7.741 14.99495 ZT4-7 17.3213 17.3213 17.3213 ZT8-11 16.77735 16.77735 16.77735 ZT12-15 20.075625000000002 19.28585 20.8654 ZT16-19 11.739460000000001 11.739460000000001 11.739460000000001 ZT20-23 17.98265 17.98265 17.98265