condition mean min max ZT0-3 9.387254 9.387254 9.387254 ZT4-7 9.678460000000001 9.678460000000001 9.678460000000001 ZT8-11 9.340072500000002 9.340072500000002 9.340072500000002 ZT12-15 8.728892 8.728892 8.728892 ZT16-19 8.939994 8.939994 8.939994 ZT20-23 8.885311000000002 8.885311000000002 8.885311000000002